Answer:
I'd say elastic
Metallic atomic solids, forming metal objects, can pass electric currents through, need a lot of heat to melt, and since electricity can easily pass through, it's quite tough/impossible to find an insulating point.
Identify the acid, base, conjugate acid and conjugate base in the following reactions:
a. NH_3(aq) + CH_3COOH(aq) NH_4^+ (aq) + CH_3COO^-(aq)
b. HClO_4(aq) + NH_4(aq) ClO_4^- (aq) + NH_4^+ (aq)
Answer:
a. NH₃ : base
CH₃COOH (acetic acid) : acid
NH₄⁺ : conjugate acid
CH₃COO⁻ : conjugate base
b. HClO₄ (perchloric acid) : acid
NH₃ : base
ClO₄⁻ : conjugate base
NH₄⁺ : conjugate acid
Hope this helps.
why Al is a member of group 13 rather than group 3?
Answer:
Boron and Aluminium
Explanation:
Boron and Aluminium are present in Group 13 of the modern periodic table. Group 13 (IUPAC System) can also be referred to as Group III-A. Logically, Boron and Aluminum can't be placed alongwith elements such as Yttrium as they don't exhibit properties of a transition metal.
Calculate the percent ionization of nitrous acid in a solution that is 0.249 M in nitrous acid. The acid dissociation constant of nitrous acid is
Answer:
4.26 %
Explanation:
There is some info missing. I think this is the original question.
Calculate the percent ionization of nitrous acid in a solution that is 0.249 M in nitrous acid. The acid dissociation constant of nitrous acid is 4.50 × 10 ⁻⁴.
Step 1: Given data
Initial concentration of the acid (Ca): 0.249 M
Acid dissociation constant (Ka): 4.50 × 10 ⁻⁴
Step 2: Write the ionization reaction for nitrous acid
HNO₂(aq) ⇒ H⁺(aq) + NO₂⁻(aq)
Step 3: Calculate the concentration of nitrite in the equilibrium ([A⁻])
We will use the following expression.
[tex][A^{-} ] = \sqrt{Ca \times Ka } = \sqrt{0.249 \times 4.50 \times 10^{-4} } = 0.0106 M[/tex]
Step 4: Calculate the percent ionization of nitrous acid
We will use the following expression.
[tex]\alpha = \frac{[A^{-} ]}{[HA]} \times 100\% = \frac{0.0106M}{0.249} \times 100\% = 4.26\%[/tex]
What is the freezing point of an aqueous solution that boils at 105.9 ∘C? Express your answer using two significant figures.
Answer:
THE FREEZING POINT OF THE AQUEOUS SOLUTION IS - 7.3 °C
Explanation:
To solve this problem, we must know the following variables:
Normal boiling point of water (solvent) = 100 °C
The molar boiling point elevation constant of water = 1.51 °C /m
Normla freezing point of water ( solvent) = 0 °C
The molar freezing point depression constant = 1.86 °C /m
The boiling point of the aqueous solution = 105.9 °C
Molarity = xM
Change in boiling point = boiling point of solution - boiling point of water
Change in boiling point = 105.9 - 100 °C
= 5.9 °C
From the formula:
Change in boiling point = i * Kb * M
Re- arranging the formula by making M the subject of the equation, we have:
M = change in boiling point / Kb
i = 1
M = 5.9 °C / 1.51 °C/m
M = 3.907 M
Then, we calculate the freezing point:
Change in freezing point = i * Kb * M
= 1 * 1.86 °C/m * 3.907 M
= 7.267 °C
Hence, the freezing point = freezing point of water - change in freezing point
Freezing point = 0 °C - 7.267 °C
Freezing point = - 7.267 °C
Freezing point = -7.3 °C
Consider the following precipitation reaction occurring in aqueous solution:
3 SrCl2(aq)+2 Li3PO4(aq) →Sr3(PO4)2(s)+6 LiCl(aq)
Write the complete ionic equation and the net ionic equation for this reaction.
Answer:
[tex]3Sr^{+2}+6Cl^{-}+6Li^{+}+2PO_{4}^{3-}-->Sr_{3}(PO_{4})_{2}+6Li^{+}+6Cl^{-}\\\\3Sr^{+2}+2PO_{4}^{3-} --->Sr_{3}(PO_{4})_{2}[/tex]
First equation is the complete ionic equation.
Second equation is the net ionic equation.
Identify the following substances:
(1) An acidic gas which gives dense white fumes with NH3
(11 An alkane which can also be called a green house gas.
(iii) A solid which when kept in the open, forms a solution after som
(iv) An alloy used in electrical fittings.
(v) A metal which gives hydrogen gas on reacting with both dilute a
Write equations for the following reactions:
Aluminium oxide and Sodium hydroxide.
(ii) Zine and dilute sulphuric acid.
(
11
Answer:
1) HCl (Hydrochloric acid reacts with NH3 and forms dense fumes)
2) Methane (It is from the group of alkanes and is a green house gas)
3) Deliquescent substance (It is a solid which when kept in open forms a solution after sometime)
4) Brass (It is a solid-in-solid solution used to make electrical fittings)
5) Aluminium
Question 2:
1) Al₂O₃ + 2NaOH ⇒ 2NaAlO₂ (Sodium Aluminate) + H₂O
2) Zn + H₂SO₄ (dilute) => ZnSO₄ (Zinc Sulphate) + H₂
Answer:
HCl is the gasmethanedeliquescent substances (they absorbs water out of the air until they dissolve themselves into liquid solutions. )brassequations
Aluminium oxide and Sodium hydroxide react to form water and sodium aluminate
Al2O3 + 2NaOH → 2NaAlO2 + H2OZinc reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas
Zn + H2SO4 → ZnSO4 +H2
Question 4 (2 points)
CuO(s) + H2(g)
Cu(s) +
H2O(1)
Balance the equation
Answer:
CuO(s) + H₂(g) --> Cu(s) + H₂O(l)
Explanation:
It is already balanced. You can see that the values of the elements of the reactants are equal to the values of the elements of the products.
Many free radicals combine to form molecules that do not contain any unpaired electrons. The driving force for the radical–radical combination reaction is the formation of a new electron‑pair bond. Consider the formation of hydrogen peroxide. 2OH(g)⟶H2O2(g) Write Lewis formulas for the reactant and product species in the chemical equation. Include nonbonding electrons.
Answer:
In the attached image the Lewis equation is shown where it is shown how two oxygens react with two hydrogens to meet the octet of the electrons.
Explanation:
Hydrogen peroxide is one of the most named chemicals since it is not only sold as "hydrogen peroxide" in pharmacies but it is also one of the great weapons of immune defense cells to defend ourselves against anaerobic bacteria.
The disadvantage of this compound is that when dividing it forms free oxygen radicals that are considered toxic or aging for our body.
In the attached image below, you will see the Lewis equation is shown there. There, you will see how two oxygens react with two hydrogens to come about the octet of the electrons.
When two or more atoms bond with each other, they often form a molecule. When two hydrogens and an oxygen share electrons through covalent bonds, a water molecule is formed.
The octet rule is known as when most atoms want to gain stability in their outer most energy level by filling themselves that is the S and P orbitals of the highest energy level with eight electron.
HOOH is the compound that is form. It is called Hydrogen peroxide. This because it is has reactive oxygen species and the simplest peroxide.
Lear more from
https://brainly.com/question/15715780
g The most common position for an double bond in an unsaturated fatty acid is delta _________(fill in the number).
Answer:
The most common position for an double bond in an unsaturated fatty acid is delta 9 (Δ⁹)
Explanation:
Unsaturated fatty acids are carboxylic acids which contains one or more double bonds. The chain length as well as the number of double bonds is written separated by a colon. The positions of the double bonds are specified starting from the carboxyl carbon, numbered as 1, by superscript numbers following a delta (Δ). For example, an 18-carbon fatty acid containing a single double bond between carbon number 9 and 10 is written as 18:1(Δ⁹).
In most monounsaturated fatty acids, the double bond is between C-9 and C-10 (Δ⁹), and the other double bonds of polyunsaturated fatty acids are generally Δ¹² and Δ¹⁵. This positioning is due to the nature of the biosynthesis of fatty acids. In the mammalian hepatocytes, double bonds are introduced easily into fatty acids at the Δ⁹ position, but cannot introduce additional double bonds between C-10 and the methyl-terminal end. However, plants are able to introduce these additional double bonds at the Δ¹² and Δ¹⁵ positions.
A substance used as a cleaner and a fuel is 37.48% C, 49.93% O and 12.58% H by mass. A 0.2804-g sample of the substance occupies a volume of 250.0 mL when it is vaporized at 75o C and 1.00 atm of pressure.
R = 0.0821 L atm/ mol K
a) This compound can be made by combining gaseous carbon monoxide with hydrogen gas (with this compound as the only product). What is the maximum mass of this compound that can be prepared if 8.0 kg of hydrogen gas react with 59.0 kg of carbon monoxide gas?
b) If 59.6 kg of the product is actually produced, given the reaction described in (a), what is the percent yield?
c) This compound (the substance you identified in part a) is a potential replacement for gasoline. The products of the complete combustion of this fuel are the same as those for the complete combustion of a hydrocarbon (CO2 and H2O). Calculate the volume of CO2 produced at 27o C and 766 mmHg when 1.00 gallon of this fuel is completely combusted. The density of the fuel is 0.7914 g/mL. 1 gallon = 3.785 liters
d) A claim was made that this fuel is better for the environment because it produces less CO2 per gallon than gasoline, which can be represented by the formula C8H18 (octane). Is this claim true? Octane has a density of 0.6986 g/mL
Answer:
Explanation:
We shall find out the molecular formula of the substance .
Ration of number of atoms of C , O and H
= [tex]\frac{37.48}{12} :\frac{49.93}{16} :\frac{12.58}{1}[/tex]
= 3.12 : 3.12 : 12.58
= 1 : 1 : 4
volume of gas at NTP
= 250 x 273 / 350 mL .
= 195 mL .
Molecular weight of the substance = .2804 x 22400 / 195 g
= 32. approx
Let the molecular formula be
(COH₄)n
n x 32 = 32
n = 1
Molecular formula = COH₄
The compound appears to be CH₃OH
a )
CO + 2H₂ = CH₃OH
28g 4g 32g
59 8
For 8 kg hydrogen , CO required = 56 kg
CO is in excess . hydrogen is the limiting reagent .
mass of product formed
= 32 x 8 / 4
= 64 kg
b )
percentage yield = product actually formed / product to be formed theoretically x 100
= 59.6 x 100 / 64
= 93.12 %
c )
2CH₃OH + 3O₂ = 2CO₂ + 4H₂O .
64 g 2 x 22.4 L
Gram of gas in 1 gallon of fuel
= .7914 x 3785
= 2995.5 g
CO₂ produced at NTP by 2995.5 g CH₃OH
= 2 x 22.4 x 2995.5 / 64 L
= 2096.85 L
At 27° C and 766 mm Hg , this volume is equal to
2096.85 x 300 x 760 / 273 x 766
= 2286.18 L .
d )
C₈H₁₈ = 8CO₂
114g 8 x 22.4 L
gram of fuel per unit gallon
= .6986 x 3785
= 2644.2g
gram of CO₂ produced by 1 gallon of fuel at NTP
= 8 x 22.4 x 2644.2 / 114
= 4156.5 L
So it produces more CO₂ .
Which of the following is NOT a type of crystal structure? A. None of these B. Metallic C. Ionic D. Macromolecular (giant covalent)
Answer:
A. None of these.
Explanation:
A crystal structure is an arrangement of atoms or ions in a repeating three-dimensional array.
B. is wrong. Metal atoms, such as gold, arrange themselves into a crystal structure.
C. is wrong. Ionic solids, such as sodium chloride, arrange themselves into a crystal structure.
D. is wrong. Macromolecules (network solids), such as diamond, arrange themselves into a crystal structure.
The correct answer is None of these.
What is a crystal structure?A crystal structure is a three-dimensional collection of atoms or ions that repeats itself.Metal atoms(gold), Ionic solids (sodium chloride), and Macromolecules(network solids) arrange themselves into a crystal structure.Learn more about crystal structure here:-
https://brainly.com/question/23986315
#SPJ2
A 1.555-g sample of baking soda decomposes with heat to produce 0.991 g Na2CO3. Refer to Example Exercise 14.l and show the calculation for the theoretical yield of Na2CO3.
What is the percent yield of sodium carbonate, Na2CO3?
6. A 1473-g unknown mixture with baking soda is heated and has a mass loss of 0.325 g. Refer to Example Exercise 14.2 and show the calculation for the percentage NaHCOs in the mixture.
Answer:
a) 101%
b)59.7%
Explanation:
The equation for the thermal decomposition of baking soda is shown;
2NaHCO3 → Na2CO3 + H2O + CO2
Number of moles of baking soda= mass/molar mass= 1.555g/84.007 g/mol = 0.0185 moles
From the reaction equation;
2 moles of baking soda yields 1 mole of sodium carbonate
0.0185 moles of baking soda will yield = 0.0185 moles ×1 /2 = 9.25 ×10^-3 moles of sodium carbonate.
Therefore, mass of sodium carbonate= 9.25 ×10^-3 moles × 106gmol-1= 0.9805 g of sodium carbonate. This is the theoretical yield of sodium carbonate.
%yield = actual yield/theoretical yield ×100
% yield = 0.991/0.9805 ×100
%yield = 101%
Since ;
2NaHCO3 → Na2CO3 + H2O + CO2
And H2O + CO2 ---> H2CO3
Hence I can write, 2NaHCO3 → Na2CO3 + H2CO3
Molar mass of H2CO3= 62.03 gmol-1
Molar mass of baking soda= 84 gmol-1
Therefore, mass of baking soda=
0.325/62.03 × 2 × 84 = 0.88 g of NaHCO3
% of NaHCO3= 0.88/1.473 × 100 = 59.7%
The decomposition reaction of baking soda is a reaction in which water and carbon dioxide ae given off as gaseous products.
5. The theoretical yield of Na₂CO₃ is approximately 0.9809 gramsThe percentage yield of sodium carbonate is approximately 101.02%.6. Percentage of NaHCO₃ in the mixture is approximately 59.76%.Reasons:
Mass of baking soda = 1.555 g
Mass of Na₂CO₃ produced = 0.991 g
Required:
Calculation for the theoretical yield
Solution:
Theoretical yield (mass) of Na₂CO₃ produced is found as follows;
Molar mass of Na₂CO₃ = 105.9888 g/mol
Molar mass of NaHCO₃ = 84.007 g/mol
[tex]\displaystyle 1.555 \, g \, NaHCO_3 \times \frac{1 \, mol \, NaHCO_3}{84.007 \, g \, NaHCO_3} \times \frac{1 \, mol \, Na_2CO_3}{2 \, mol \, NaHCO_3} \times 105.9888 \ g \approx 0.9809 \, g \, Na_2CO_3[/tex]
The theoretical yield of Na₂CO₃ ≈ 0.9809 grams.
The percentage yield is given as follows;
[tex]\displaystyle Percentage \ yield = \mathbf{\frac{Actual \, Yield}{Theorectical \, Yield} \times 100 \%}[/tex]
The percentage yield of Na₂CO₃ is therefore;
[tex]\displaystyle Percentage \ yield \ of \ Na_2CO_3= \frac{0.991}{0.9809} \times 100 \% \approx \underline{ 101.02 \%}[/tex]
(Some baking soda may remain if the reaction is not completed)
6. Mass of the unknown mixture of baking soda = 1473 g
Mass loss from the mixture = 0.325 g
Required:
The percentage of NaHCO₃ in the mixture.
Solution:
The chemical in the mass loss from heating the NaHCO₃ = H₂CO₃
Molar mass of H₂CO₃ = 62.03 g/mol
[tex]\displaystyle \mathrm{Number \ of \ moles \ of \ H_2CO_3 \ produced} = \frac{0.325 \, g}{62.03 \, g/mol} \approx 5.2394 \times 10^{-3} \ moles[/tex]
The chemical reaction is presented as follows;
2NaHCO₃(s) [tex]\underrightarrow {\Delta \ Heated}[/tex] Na₂CO₃(s) + H₂CO₃(g)2 moles of NaHCO₃ produces 1 mole of H₂CO₃The number of moles of NaHCO₃ in the mixture is therefore;
2 × 5.2394 × 10⁻³ moles ≈ 1.04788 × 10⁻² molesMass of NaHCO₃ in the mixture is therefore
Mass of NaHCO₃ = 1.04788 × 10⁻² moles × 84.007 g/mol = 0.88029 g[tex]\displaystyle Percentage \ of \ NaHCO_3 \ in \ the \ mixture \ = \mathbf{ \frac{Mass \ of \ NaHCO_3}{Mass \ of \ mixture} \times 100}[/tex]
Which gives;
[tex]\displaystyle Percentage \ of \ NaHCO_3 \ in \ the \ mixture \ = \ \frac{0.88029 \, g}{1.473 \, g} \times 100 \approx \underline{ 59.76 \%}[/tex]Learn more here:
https://brainly.com/question/21091465
What is the shape of a molecule that has 4 atoms bonded to a central atom
and no lone pairs of electrons?
A. Octahedral
B. Cubic
C. Tetrahedral
D. Trigonal-pyramidal
Answer:
C. Tetrahedral
Explanation:
Tetrahedral would be the correct choice because the central atom has 4 domains (1 bond counts as 1 domain so 4 bonds =4) and no lone pairs which means it has tetra (which translates to four) domains hence tetrahedral.
Tetrahedral is the shape of a molecule that has 4 atoms bonded to a central atom and no lone pairs of electrons. Hence, option C is correct.
What is an atom?An atom consists of a central nucleus that is usually surrounded by one or more electrons.
Tetrahedral would be the correct choice because the central atom has 4 domains (1 bond counts as 1 domain so 4 bonds =4) and no lone pairs which mean it has tetra (which translates to four) domains hence tetrahedral.
Hence, option C is correct.
Learn more about atom here:
https://brainly.com/question/1566330
#SPJ2
At 25.0°C the Henry's Law constant for methane CH4 gas in water is ×1.410−3/Matm.
Calculate the mass in grams of CH4 gas that can be dissolved in 75.mL of water at 25.0°C and a CH4 partial pressure of 0.68atm. Round your answer to 2 significant digits.
Answer:
1.1 × 10⁻³ g
Explanation:
Step 1: Given data
Henry's Law constant for methane (k): 1.4 × 10⁻³ M/atm
Volume of water (=volume of solution): 75 mL
Partial pressure of methane (P): 0.68 atm
Step 2: Calculate the concentration of methane in water (C)
We will use Henry's law.
[tex]C = k \times P = 1.4 \times 10^{-3}M/atm \times 0.68atm = 9.5 \times 10^{-4}M[/tex]
Step 3: Calculate the moles of methane in 75 mL of water
[tex]\frac{9.5 \times 10^{-4}mol}{L} \times 0.075 L = 7.1 \times 10^{-5}mol[/tex]
Step 4: Calculate the mass corresponding to 7.1 × 10⁻⁵ mol of methane
The molar mass of methane is 16.04 g/mol.
[tex]7.1 \times 10^{-5}mol \times \frac{16.04g}{mol} = 1.1 \times 10^{-3} g[/tex]
Therapeutic drugs generally need to have some hydrophobic and hydrophilic components to be able to effectively reach their target organs and tissues given there are aqueous and nonaqueous parts of the body. The degree to which a compound is hydrophobic and hydrophilic can be determined by measuring its relative solubility in water and octanol, C8H17OH, and water. To do this, a sample of the compound is added to a mixture of water and octanol and mixed well. Water and octanol are immiscible so after the mixture settles, the concentration of the compound in water and the concentration of the compound in octanol is measured. The ratio of the concentrations is called the partition ratio:
The question is incomplete as some part is missing:
concentration in octanol Partition Ratio = concentration in water
a) What are the intermolecular forces of attraction between octanol molecules? Explain.
b) Which of the intermolecular forces of attraction identified in (a) account for most of the interactions between octanol molecules? Explain. Use the immiscibility in water and the data included in figures 1 and 2 as evidence to support your answer.
c) Would a compound with a partition coefficient less than one be more hydrophobic or more hydrophilic than one with a partition coefficient greater than 10? Explain.
d) Would nonane (figure 2) be more soluble in water or octanol? Explain.
e) Draw another structure for a compound with the same chemical formula as nonane (CH20) that has a lower boiling point. Explain.
f) Are any of the C atoms in the structure you drew for CH20 sp?hybridized? Explain.
Octanol Boiling point = 195°C Figure 2 Nonane (CH20) Boiling point = 151°C
Answer:
1. The forces between octanol molecules would be attractive. These forces include Vanderwaal forces, H-bonds due to the presence of highly polar O-H group.
2. H-bonding ahould account for most of the attractive forces. The O-H bond should behave like and dipole, oxygen of one molecule attracts the hydrogen of the neighbouring molecule forming D-H...A links throughout (D stands for donor of H-Bond and A for acceptor for H-Bond).
3. Partition coefficient less than 1 will be more hydrophilic, generally drugs with low partition coefficients are regarded as hydrophilic. As parition coefficient of 10 mean more of the solute is dispersed in octanol as compared to water.
4. Nonane is non polar, so it would not dissolve in water. It follows the rule like dissolves like. Polar substances dissolve in polar solvents. 1-octanol is able to bind with water through hydrogen bonds thus its soluble in water but nonane doesn't. Nonane will forms a different layer from water.
5) no all carbons in 2-methyloctane are single bonded. Thus sp3 hybrid. A sp2 hybridised carbon would have a double bond C=C.
A solution is prepared by adding 6.24 g of benzene (C 6H 6, 78.11 g/mol) to 80.74 g of cyclohexane (C 6H 12, 84.16 g/mol). Calculate the mole fraction and molality of benzene in this solution.
Answer:
[tex]x_B=0.0769[/tex]
[tex]m=0.990m[/tex]
Explanation:
Hello,
In this case, we can compute the mole fraction of benzene by using the following formula:
[tex]x_B=\frac{n_B}{n_B+n_C}[/tex]
Whereas n accounts for the moles of each substance, thus, we compute them by using molar mass of benzene and cyclohexane:
[tex]n_B=6.24g*\frac{1mol}{78.11g}=0.0799mol\\ \\n_C=80.74g*\frac{1mol}{84.16g} =0.959mol[/tex]
Thus, we compute the mole fraction:
[tex]x_B=\frac{0.0799mol}{0.0799mol+0.959mol}\\ \\x_B=0.0769[/tex]
Next, for the molality, we define it as:
[tex]m=\frac{n_B}{m_C}[/tex]
Whereas we also use the moles of benzene but rather than the moles of cyclohexane, its mass in kilograms (0.08074 kg), thus, we obtain:
[tex]m=\frac{0.0799mol}{0.08074kg}=0.990mol/kg[/tex]
Or just 0.990 m in molal units (mol/kg).
Best regards.
Considering the definition of mole fraction and molality:
the mole fraction of benzene is 0.077.the molality of benzene is 0.9908 [tex]\frac{moles}{kg}[/tex].You know that:
Mass of benzene = 6.24 gramsMass of cyclohexane= 80.74 gramsMolar mass of benzene= 78.11 g/moleMolar mass of cyclohexane= 84.16 g/moleMole fractionThe molar fraction is a way of measuring the concentration that expresses the proportion in which a substance is found with respect to the total moles of the solution.
Being the molar mass and the mass in the solution of each compound, the number of moles of each compound can be calculated as:
Benzene: [tex]\frac{mass of benzene}{molar mass of benzene} =\frac{6.24 grams}{78.11 \frac{grams}{mole} } = 0.08 moles[/tex]Cyclohexane:[tex]\frac{mass of cyclohexane}{molar mass of ciclohexane} =\frac{80.74 grams}{84.16\frac{grams}{mole} } = 0.96 moles[/tex]So, the total moles of the solution can be calculated as:
Total moles = 0.08 moles + 0.96 moles = 1.04 moles
Finally, the mole fraction of benzene can be calculated as follow:
[tex]\frac{number moles of benzene}{total moles} =\frac{0.08 moles}{1.04 moles} = 0.077[/tex]
Finally, the mole fraction of benzene is 0.077.
MolalityMolality is the ratio of the number of moles of any dissolved solute to kilograms of solvent.
The Molality of a solution is determined by the expression:
[tex]Molality=\frac{number of moles of solute}{kilograms of solvent}[/tex]
In this case, you know:
number of moles of solute= 0.08 moles Mass of solvent = 80.74 g = 0.08074 kg (being 1000 g=1 kg)Replacing:
[tex]Molality benzene=\frac{0.08 moles}{0.08074 kg}[/tex]
Molality benzene= 0.9908 [tex]\frac{moles}{kg}[/tex]
Finally, the molality of benzene is 0.9908 [tex]\frac{moles}{kg}[/tex].
Learn more about:
mole fraction brainly.com/question/14434096?referrer=searchResults brainly.com/question/10095502?referrer=searchResults molality brainly.com/question/20366625?referrer=searchResults brainly.com/question/4580605?referrer=searchResults
please help me I am begging you.. )))): PLEASE HELP ME ~~~~~~~~~~~~~~~~~~~~~~ A football player experiences acute pain in his knee. Which of the following methods can a doctor use to diagnose the reason for the pain? --_-_-____- A.) Use infrared radiation from warm objects to look inside the knees. B.) Use radio waves emitted by radioactive substances to look at bones. C.) Use radiations emitted by very hot objects to penetrate the skin and bones. D.) Use x‒ray radiation to see if there are any fractured bones.
Answer:
D. Use x-ray radiation to see if there are any fractured bones.
Explanation:
The football player may have fractured a bone while he was practicing or playing, so it is best for the doctor to check if the player broke his bone or fractured it.
An electrode has a negative electrode potential. Which statement is correct regarding the potential energy of an electron at this electrode?
A. An electron at this electrode has the same potential energy as it has at a standard hydrogen electrode.
B. An electron at this electrode has a lower potential energy than it has at a standard hydrogen electrode.
C. An electron at this electrode has a higher potential energy than it has at a standard hydrogen electrode.
Answer:
C. An electron at this electrode has a higher potential energy than it has at a standard hydrogen electrode.
Explanation:
The standard hydrogen electrode (SHE) is used to measure the electrode potential of substances. The standard hydrogen electrode is arbitrarily assigned an electrode potential of zero. Recall that electrode potentials are always measured as reduction potentials in electrochemical systems.
For an electrode that has a negative electrode potential, electrons at this electrode have a higher potential energy compared to electrons at the standard hydrogen electrode. Electrons flow from this electrode to the hydrogen electrode.
On the other hand, a positive electrode potential implies that an electron at this electrode has a lower potential energy than it has at a standard hydrogen electrode. Hence electrons will flow from the standard hydrogen electrode to this electrode.
Which element has 4 valence electrons in the 3p sublevel?
The Periodic Table
A. Ga
B. Si
C. N
D. S
Answer:
D . Sulphur
Explanation:
the element with a 3p4 valence configuration, look in period 3 and group XVI, and that is ...
S, sulfur.
If you combine 24.2 g of a solute that has a molar mass of 24.2 g/mol with 100.0 g of a solvent, what is the molality of the resulting solution
Answer: 10 moles/kg.
Explanation:
Given, Mass of solute = 24.2 g
Molar mass of solute = 24.2 g/mol
[tex]\text{Moles of solute =}\dfrac{\text{Mass of solute}}{\text{Molar mass of solute}}\\\\=\dfrac{24.2}{24.2}=1[/tex]
Mass of solvent = 100.0g = 0.1 kg [1 g=0.001 kg]
[tex]\text{Molality}=\dfrac{\text{Moles of solute}}{\text{kilograms of Solvent}}\\\\=\dfrac{1}{0.1}\\\\=10\ moles/kg[/tex]
Hence, the molality of the resulting solution is 10 moles/kg.
A sample of a pure compound that weighs 60.3 g contains 20.7 g Sb (antimony) and 39.6 g F (fluorine). What is the percent composition of fluorine
Answer:
The percent composition of fluorine is 65.67%
Explanation:
Percent Composition is a measure of the amount of mass an element occupies in a compound. It is measured in percentage of mass.
That is, the percentage composition is the percentage by mass of each of the elements present in a compound.
The calculation of the percentage composition of an element is made by:
[tex]percent composition element A=\frac{total mass of element A}{mass of compound} *100[/tex]
In this case, the percent composition of fluorine is:
[tex]percent composition of fluorine=\frac{39.6 g}{60.3 g} *100[/tex]
percent composition of fluorine= 65.67%
The percent composition of fluorine is 65.67%
Answer:
The percent composition of fluorine is 65.67%
Explanation:
Percent Composition is a measure of the amount of mass an element occupies in a compound. It is measured in percentage of mass.
That is, the percentage composition is the percentage by mass of each of the elements present in a compound.
The calculation of the percentage composition of an element is made by:
In this case, the percent composition of fluorine is:
percent composition of fluorine= 65.67%
The percent composition of fluorine is 65.67%
Determine the rate of a reaction that follows the rate law:
rate = k[A]”[B]", where:
k= 1.5
[A] = 1 M
[B] = 3 M
m = 2
n = 1
Answer:
k= 1.5
[A] = 1 M
[B] = 3 M
m = 2
n = 1
Explanation:
rate = k[A]”[B]"
The rate of the reaction is 4.5 mol L⁻¹s⁻¹.
What is meant by rate of a reaction ?Rate of a reaction is defined as the change in concentration of any one of the reactants or products of the reaction, in unit time.
Here,
The concentration of A, [A] = 1 M
The concentration of B, [B] = 3 M
The partial order with respect to A, m = 2
The partial order with respect to B, n = 1
The rate constant of the reaction, k = 1.5
The rate of the reaction,
r = k[A]^m [B}^n
r = 1.5 x 1² x 3
r = 4.5 mol L⁻¹s⁻¹
Hence,
The rate of the reaction is 4.5 mol L⁻¹s⁻¹.
To learn more about rate of a reaction, click:
https://brainly.com/question/29049197
#SPJ2
Name MgSo4.7H2O /Cs3PO4.H2O
Answer:
MgSo4.7H2O = Magnesium sulfate
Cs3PO4.H2O = Cesium Phosphate
Hope this helps!
The distance from the Moon to Earth is 5.46 * 108 km. How long does it take a laser need to travel between the moon and earth?
a. 1.64 X 1020 s
b. 1.82 X 103 s
c. 1.82 s
d. 0.182 s
e. 1.64 X 1017 s
Answer:
B. 1.82(10³) seconds (1820 seconds)
Explanation:
Speed of Light: 3.00(10⁸) m/s or 3.00(10⁵) km/s
We know the distance from the Moon to Earth as 5.46(10⁸) km
We simply divide the distance by the speed of light:
[tex]\frac{5.46(10^8)}{3.00(10^5)}[/tex]
We should get 1820 seconds or B. 1.82(10³) as our answer.
Consider 1 M solutions of NaCl, ethyl alcohol (CH3CH2OH), and hydrofluoric acid. Rank them in terms of how well they conduct electricity and explain why you ranked them this way.
Answer:
conductivity increasing order CH₃-CH₂-OH < HF< NaCl
Explanation:
NaCl is the better conductor comparing with remaining two. it is strong electrolyte. dissociation percent always nearly eqaul to 100% but HF is weaker acid than NaCl and dissociation percent <100% . So, the no of ions furnished by HF less than that of NaCl
CH₃-CH₂-OH organic compound . in general it is not treated as an electrolyte and it cannot carry any charge. If it carries, it is very very less compared to remaining two
Determine the radius of an Al atom (in pm) if the density of aluminum is 2.71 g/cm3 . Aluminum crystallizes in a face centered cubic structure with an edge leng
Answer:
143pm is the radius of an Al atom
Explanation:
In a face centered cubic structure, FCC, there are 4 atoms per unit cell.
First, you need to obtain the mass of an unit cell using molar mass of Aluminium and thus, obtain edge length and knowing Edge = √8R you can find the radius, R, of an Al atom.
Mass of an unit cell
As 1 mole of Al weighs 26.98g. 4 atoms of Al weigh:
4 atoms × (1mole / 6.022x10²³atoms) × (26.98g / mole) = 1.792x10⁻²²g
Edge length
As density of aluminium is 2.71g/cm³, the volume of an unit cell is:
1.792x10⁻²²g × (1cm³ / 2.71g) = 6.613x10⁻²³cm³
And the length of an edge of the cell is:
∛6.613x10⁻²³cm³ = 4.044x10⁻⁸cm = 4.044x10⁻¹⁰m
Radius:
As in FCC structure, Edge = √8 R, radius of an atom of Al is:
4.044x10⁻¹⁰m = √8 R
1.430x10⁻¹⁰m = R.
In pm:
1.430x10⁻¹⁰m ₓ (1x10¹²pm / 1m) =
143pm is the radius of an Al atomThe radius of the atom of Al in the FCC structure has been 143 pm.
The FCC lattice has been contributed with atoms at the edge of the cubic structure.
The FCC has consisted of 4 atoms in a lattice.
The mass of the unit cell of Al can be calculated as:[tex]\rm 6.023\;\times\;10^2^3[/tex] atoms = 1 mole
4 atoms = [tex]\rm \dfrac{4}{6.023\;\times\;10^2^3}[/tex] moles
The mass of 1 mole Al has been 26.98 g/mol.
The mass of [tex]\rm \dfrac{4}{6.023\;\times\;10^2^3}[/tex] moles = [tex]\rm \dfrac{4}{6.023\;\times\;10^2^3}[/tex] moles × 26.98 g
The mass of 1 unit cell of Al has been = 1.792 [tex]\rm \bold{\times\;10^-^2^2}[/tex] g.
The volume of the Al cell can be calculated as:Density = [tex]\rm \dfrac{mass}{volume}[/tex]
Volume = Density × Mass
The volume of Al unit cell = 2.71 g/[tex]\rm cm^3[/tex] × 1.792 [tex]\rm \times\;10^-^2^2[/tex] g
The volume of Al cell = 6.613 [tex]\rm \times\;10^-^2^3[/tex] [tex]\rm cm^3[/tex]
The volume of the cube has been given as:Volume = [tex]\rm edge\;length^3[/tex]
6.613 [tex]\rm \times\;10^-^2^3[/tex] [tex]\rm cm^3[/tex] = [tex]\rm edge\;length^3[/tex]
Edge length = [tex]\rm \sqrt[3]{6.613\;\times\;10^-^2^3}[/tex] cm
Edge length = 4.044 [tex]\rm \times\;10^-^8[/tex] cm
Edge length = 4.044 [tex]\rm \bold{\times\;10^-^1^0}[/tex] m.
In an FCC lattice structure, the radius of the atom can be given by:Edge length = [tex]\rm \sqrt{8\;\times\;radius}[/tex]
4.044 [tex]\rm \bold{\times\;10^-^1^0}[/tex] m = [tex]\rm \sqrt{8\;\times\;radius}[/tex]
Radius = 1.430 [tex]\rm \bold{\times\;10^-^1^0}[/tex] m.
1 m = [tex]\rm 10^1^2[/tex] pm
1.430 [tex]\rm \bold{\times\;10^-^1^0}[/tex] m = 143 pm.
The radius of the atom of Al in the FCC structure has been 143 pm.
For more information about the FCC structure, refer to the link:
https://brainly.com/question/14934549
Which best describes the trends in electonegativity on the periodic table
Hey! :)
__________ ☆ ☆__________________________________
Answer:
The answer is Electronegativity increases up and to the right
Explanation:
When you move from left to right it increases ( in the periodic table )
But when you move down the table electronegativity decreases.
So “ Electronegativity increases up and to the right” describes the trends the best.
Hope this helps! :)
____________☆ ☆________________________________
By, BrainlyMember ^-^
Good luck!
To condition the buret, add a small volume of ____________ to the buret and rotate the barrel ____________ so that the liquid makes contact with the full inner surface of the barrel. Complete this action _________ and discard each volume in a designated waste container.
Answer:
Acid, Horizontally, Drain off the acid by opening the stopcock
Explanation:
A buret is a calibrated glass appratus used to measure and deliver accurate volume of liquid, usually acids, in acid-base titrations.
Before usually the buret to carry out your titration reaction, it is advised to condition or prepare your buret for use.
To condition the buret, add a small volume of the acid to the buret and rotate the barrel horizontally to ensure that the liquid ( acid) makes contact with the inner surface of the barrel o the buret.
This procedure is done to wash off any previous acid or liquid that the buret had been used for in previous titrations.
Complete this action by opening the stopcock of the buret to drain off the acid and discarding each volume in a designated waste container.
Note that acids could be corrosive and dangerous to the skin and so should be handled with great care
Classify each molecule by whether its real bond angles are the same as or different than its model (ideal) bond angles. In other words, do the bond angles change when you switch between Real and Model mode at the top of the page?
The question is incomplete; the complete question is: Classify each molecule by whether its real bond angles are the same as or different than its model (ideal) bond angles. In other words, do the bond angles change when you switch between Real and Model mode at the top of the page? Same (angles do not change) Different (angles change) Answer Bank | H2O | CO2, SO2, XeF2, BF3 CIF3, NH3, CH4, SF4, XeF4, BrF5, PCI5,SF6
Answer:
Compounds whose real bond angle are the same as ideal bond angle;
SF6, BF3, CH4, PCI5
Compounds whose real bond angles differ from ideal bond angles;
H2O, CO2, SO2, XeF2, CIF3, NH3, SF4, XeF4, BrF5
Explanation:
According to the valence shell electron pair repulsion theory (VSEPR), molecules adopt various shapes based on the number of electron pairs on the valence shell of the central atom of the molecule. The electron pairs usually orient themselves as far apart in space as possible leading to various observed bond angles.
The extent of repulsion of lone pairs is greater than that of bond pairs. Hence, the presence of lone pairs on the valence shell of the central atom in the molecule distorts the bond angles of molecules away from the ideal bond angles predicted on the basis of valence shell electron pair repulsion theory.
For instance, methane is a perfect tetrahedron having an ideal bond angle of 109°28'. Both methane and ammonia are based on a tetrahedron, however, the presence of a lone pair of electrons on nitrogen distorts the bond angle of ammonia to about 107°. The distortion of lone pairs in water is even more as the bond angles of water is about 104°.
. Explain why, in the sample calculations, 0.1 g of the unknown produced a GREATER freezing point depression than~e same mass of naphthalene.
Answer
Naphthalene is a non electrolyte
If the unknown compound is an electrolyte it gives 2 or more ions in solution
( NaCl >> Na+ + Cl- => 2 ions
Ca(NO3)2 >> Ca2+ + 2 NO3- => 3 ions)
the f.p. lowering is directly proportional to the molal concentration of dissolved ions in the solution )
For naphthalene
delta T = 1.86 x m
for a salt that gives 2 ions
delta T = 1.86 x m x 2
hence the lowering in freezion point of unkown is greater then napthalene