The given question is incomplete, the complete question is:
CsCl crystallizes in a unit cell that contains the Cs+ ion at the center of a cube that has a Cl- at each corner. Each unit cell contains __________ Cs+ ions and __________ Cl-, ions, respectively.
a. 1 and 8
b. 2 and 2
c. 2 and 1
d. 2 and 4
e. 1 and 1
Answer:
The correct answer is option e, that is, 1 and 1.
Explanation:
A regular and a small geometric unit of a crystal that illustrates the repeating pattern of the crystal lattice is termed as a unit cell. Based on the given question, crystallization of CsCl takes place in a unit cell that comprises the ion of Cs+ at the center of a cube, which possesses Cl- at every corner.
In the given case, in the center of the lattice one atom of Cs is present, therefore, there is one ion of Cs for one unit cell. It is known that there are 8 corners of a cube, and Cl- ion is situated at each corner. So,
8 corners * (1 Cl ion/8 corners) = 1 Cl ion
Hence, the ratio of Cs+ : Cl- is 1:1.
Each unit cell contains 1 [tex]Cs^{+}[/tex] ion(s) and 1 [tex]Cl^{-}[/tex] ion(s), respectively.
CsCl has a cubic structure that consists of an infinite chain of ions. The Cs (or Cl) ions sit at the eight corners of the cube and the Cl (or Cs) sit at the center of the cube.
It is given that:
The Cs ion([tex]Cs^{+}[/tex]) is present at the center of a cube and [tex]Cl^{-}[/tex] is present at each corner.
It is known that there are total 8 corners in a cube and [tex]Cl^{-}[/tex] is present at each corner.
So, 8 corners * (1 [tex]Cl^{-}[/tex] ion/ 8 corners)=1 [tex]Cl^{-}[/tex] ion
And also, Cs ion at present at the center of a cube thus 1 [tex]Cs^{+}[/tex] ion for one unit cell.
Thus the ration of [tex]Cs^{+}[/tex]: [tex]Cl^{-}[/tex] is 1:1 and each unit cell contains 1 [tex]Cs^{+}[/tex] ion(s) and 1 [tex]Cl^{-}[/tex] ion(s), respectively.
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When ethanol, C2H5OH (a component in some gasoline mixtures) is burned in air, one molecule of ethanol combines with three oxygen molecules to form two CO2 molecules and three H2O molecules.
A) Write the balanced chemical equation for the reaction described.
B) How many molecules of CO2 and H2O would be produced when 2 molecules ethanol are consumed? Equation?
C) How many H2O molecules are formed, then 9 O2 molecules are consumed? What conversion factor did you use? Explain!
D) If 15 ethanol molecules react, how many molecules O2 must also react? What conversion factor did you use? Explain!
Answer:
1) C2H5OH(l)+3O2(g)⟶2CO2(g)+3H2O(l)
2) four molecules of CO2 will be produced and six molecules of water
3)9 molecules of water are formed when 9 molecules of oxygen are consumed.
4) 45 molecules of oxygen
Explanation:
The balanced chemical reaction equation is shown here and must guide our work. When ethanol is burned in air, it reacts as shown;
C2H5OH(l)+3O2(g)⟶2CO2(g)+3H2O(l)
Hence, if we use 2 molecules of ethanol, the balanced reaction equation will look like this;
2C2H5OH(l)+6O2(g)⟶4CO2(g)+6H2O(l)
Hence four molecules of CO2 are formed and six molecules of water are formed
From the balanced stoichiometric equation;
3 molecules of oxygen yields 3 molecules of water
Therefore, 9 molecules of oxygen will yield 9 × 3/3 = 9 molecules of water
Therefore, 9 molecules of water are formed when 9 molecules of oxygen are consumed.
From the reaction equation;
1 molecule of ethanol reacts with 3 molecules of oxygen
Therefore 15 molecules of ethanol will react with 15 × 3/1 = 45 molecules of oxygen
Give the ground-state electron configuration for silicon (SiSi) using noble-gas shorthand. Express your answer in condensed form as a series of orbitals. For example, [Ar]4s23d8[Ar]4s23d8 would be entered as [Ar]4s^23d^8.
Answer:
[Ne] 3s² 3p²
Explanation:
Silicon atoms have 14 electrons. The ground state electron configuration of ground state gaseous neutral silicon is 1s²2s²2p⁶3s²3p².
Using noble gas shorthand, the electronic configuration is reduced to;
[Ne] 3s² 3p². Ne s the nearest noble gas to silicon, Ne contains 8 electrons, this means there's still 4 more electrons to fill. The s orrbital can only hold 2, hence the reaing two is transferred to the p orbital.
Harvey kept a balloon with a volume of 348 milliliters at 25.0˚C inside a freezer for a night. When he took it out, its new volume was 322 milliliters, but its pressure was the same. If the final temperature of the balloon is the same as the freezer’s, what is the temperature of the freezer?
Answer:
[tex]T2=276K[/tex]
Explanation:
Given:
Initial volume of the balloon V1 = 348 mL
Initial temperature of the balloon T1 = 255C
Final volume of the balloon V2 = 322 mL
Final temperature of the balloon T2 =
To calculate T1 in kelvin
T1= 25+273=298K
Based on Charles law, which states that the volume of a given mass of a ideal gas is directly proportional to the temperature provided that the pressure is constant. It can be applied using the below formula
[tex](V1/T1)=(V2/T2)[/tex]
T2=( V2*T1)/V1
T2=(322*298)/348
[tex]T2=276K[/tex]
Hence, the temperature of the freezer is 276 K
Answer: 276 kelvins
Explanation:
zinc metal and hydrochloric acid react together according to the following equation 2HCl (aq)+ Zn(s) = ZnCl2(aq) +H2(g) if 5.98 g Zn reacts with excess HCl at 298 K and 0.978 atm what volume of H2 can be collected
Answer:
2.29 L
Explanation:
In this question we have to start with the chemical reaction:
[tex]2HCl_(_a_q_)~+~Zn_(_s_)~->~ZnCl_2_(_a_q_)~+~H_2_(_g_)[/tex]
The reaction is already balanced. So, if we have an excess of HCl the compound that would limit the production of [tex]H_2[/tex] would be Zn. So, we have to follow a few steps:
1) Convert from grams to moles (Using the atomic mass of Zn 65.38 g/mol).
2) Convert from moles of Zn to moles of [tex]H_2[/tex] (Using the molar mass 1 mol [tex]H_2[/tex] = 1 mol Zn).
3) Convert from mol of [tex]H_2[/tex] to volume (Using the ideal gas equation PV=nRT).
First step:
[tex]5.98~g~Zn\frac{1~mol~Zn}{65.38~g~Zn}=0.0915~mol~Zn[/tex]
Second step:
[tex]0.0915~mol~Zn\frac{1~mol~H_2}{1~mol~Zn}=0.0915~mol~H_2[/tex]
Third step:
We have to remember that R = 0.082 [tex]\frac{atm*L}{mol*K}[/tex] , so:
[tex]V=\frac{0.082\frac{atm*L}{mol*K}*0.0915~mol~H_2*298K}{0.978~atm}[/tex]
[tex]V=2.29~L[/tex]
I hope it helps!
Under certain conditions, the substances zinc oxide and water combine to form zinc hydroxide. If 30.1 grams of zinc oxide and 6.7 grams of water combine to form zinc hydroxide, how many grams of zinc hydroxide must form
Answer:
36.8g of Zinc hydroxide
Explanation:
Based on the reaction:
ZnO + H₂O → Zn(OH)₂
Where 1 mole of zinc oxide reacts with 1 mole of water to produce 1 mole of zinc hydroxide.
Moles of 30.1g of ZnO (FW = 81.38g/mol) are:
30.1g ZnO ₓ (1mol / 81.38g) = 0.370 moles of ZnO
And moles of 6.7g of H₂O (FW = 18.01g/mol) are:
6.7g H₂O ₓ (1mol / 18.01g) = 0.372 moles of H₂O
As 1 mole of ZnO reacts per mole of H₂O, limiting reactant is ZnO because has a less number of moles than water.
Thus, moles of Zn(OH)₂ produced are 0.370 moles.
As Molar mass of Zinc hydroxide is 99.424 g/mol, there are formed:
0.370 moles Zn(OH)₂ ₓ (99.424g / mol) =
36.8g of Zinc hydroxideHow many milliliters of 0.500 M NaOH should be added to 10.0 g of tris hydrochloride (FM 121.135) to give a pH of 7.60 in a final volume of 250 mL? pk, for the tris = 8.072
Answer:
41.64mL of NaOH 0.500M must be added to obtain the desire pH
Explanation:
It is possible to find pH of a buffer by using H-H equation, thus:
pH = pka + log [A⁻] / [HA]
Where [HA] is concentration of the weak acid TRIS-HCl and [A⁻] is concentration of its conjugate acid.
Replacing in H-H equation:
7.60 = 8.072 + log [A⁻] / [HA]
0.3373 = [A⁻] / [HA] (1)
10.0g of TRIS-HCl (Molar mass: 121.135g/mol) are:
10.0g ₓ (1mol / 121.135g) = 0.08255 moles of acid. That means moles of both the acid and conjugate base are:
[A⁻] + [HA] = 0.08255 (2)
Replacing (1) in (2):
0.3373 = 0.08255 - [HA] / [HA]
0.3373[HA] = 0.08255 - [HA]
1.3373[HA] = 0.08255
[HA] = 0.06173 moles
Thus:
[A⁻] = 0.08255 - 0.06173 = 0.02082 moles [A⁻]
The moles of A⁻ comes from the reaction of the weak acid with NaOH, that is:
HA + NaOH → A⁻ + H₂O + K⁺
Thus, you need to add 0.02082 moles of NaOH to produce 0.02082 moles of A⁻. As NaOH solution is 0.500M:
0.02082 moles NaOH ₓ (1L / 0.500mol) = 0.04164L of NaOH 0.500M =
41.64mL of NaOH 0.500M must be added to obtain the desire pHa solid x when heated gives up a brown gas. If x is soluble in excess sodium hydroxide solution but insoluble in excess ammonium hydroxide solition. What is X?
Answer:
Lead (ii) nitrate
Explanation:
It is soluble in sodium hydroxide but insoluble in aqueous ammonia
When heated it produces nitrogen (IV) oxide that isbrown in colour
How many moles of each product form when the given amount of each reactant completely reacts. C3H8(g)+5O2yields 3CO2(g)+4H2O(g). 4.6 moles of C3H8
Answer: 13.8 moles of [tex]CO_2[/tex] and 18.4 moles of [tex]H_2O[/tex] will be produced
Explanation:
The given balanced reaction is;
[tex]C_3H_8(g)+5O_2(g)\rightarrow 3CO_2(g)+4H_2O(g)[/tex]
Given : 4.6 moles of [tex]C_3H_8[/tex]
According to stoichiometry :
1 mole of [tex]C_3H_8[/tex] give = 3 moles of [tex]CO_2[/tex]
Thus 4.6 moles of [tex]C_3H_8[/tex] will give =[tex]\frac{3}{1}\times 4.6=13.8moles[/tex] of [tex]CO_2[/tex]
1 mole of [tex]C_3H_8[/tex] give = 4 moles of [tex]H_2O[/tex]
Thus 4.6 moles of [tex]C_3H_8[/tex] give =[tex]\frac{4}{1}\times 4.6=18.4moles[/tex] of [tex]H_2O[/tex]
Thus 13.8 moles of [tex]CO_2[/tex] and 18.4 moles of [tex]H_2O[/tex] will be produced from the given moles of reactant [tex]C_3H_8[/tex]
Give one example in real life when titration can be used.
A solution is prepared by dissolving 33.0 milligrams of sodium chloride in 1000. L of water. Assume a final volume of 1000. liters. Calculate the following values listed below.
a. Molarity of NaCl
b. Molarity of sodium ions
c. Molarity of chloride ions
d. Osmolarity of the solution
e. Mass percent of NaCl
f. Parts per million of sodium chloride
g. Parts per billion of sodium chloride
h. Look at your answers to parts e, f, and g.
Which one of these values is the most convenient or easiest to say and use/understand when discussing concentration.
Answer:
a. Molarity of NaCl solution = 5.64 * 10⁻⁷ mol/L
b. molarity of Na⁺ = 5.64 * 10⁻⁷ mol/L
c. molarity of Cl⁻ = 5.64 * 10⁻⁷ mol/L
d. Osmolarity = 1.128 osmol
e. mass percent of NaCl = 3.30 * 10⁻⁶ %
f. parts per million NaCl = 0.033 ppm NaCl
g. parts per billion of NaCl = 33 ppb of NaCl
h. From the values obtained from e, f and g, the most convenient to use and understand is parts per billion as it has less of a fractional part to deal with especially since the solute concentration is very small.
Explanation:
Molarity of a solution = number of moles of solute (moles)/volume of solution (L)
where number of moles of solute = mass of solute (g)/molar mass of solute (g/mol)
a. Molarity of NaCl:
molar mass of NaCl = 58.5 g/mol, mass of NaCl = 33.0/1000) g = 0.033g
number of moles of NaCl = 0.033/58.5 = 0.000564 moles
Molarity of NaCl solution = 0.000564/1000 = 5.64 * 10⁻⁷ mol/L
b. Equation for the dissociation of NaCl in solution: NaCl ----> Na⁺ + Cl⁻
From the above equation I mole of NaCl dissociates to give 1 mole of Na⁺ ions,
Therefore molarity of Na⁺ = 1 * 5.64 * 10⁻⁷ mol/L = 5.64 * 10⁻⁷ mol/L
c. From the above equation I mole of NaCl dissociates to give 1 mole of Cl⁻ ions,
therefore molarity of Cl⁻ = 1 * 5.64 * 10⁻⁷ mol/L = 5.64 * 10⁻⁷ mol/L
d. From the above equation, dissociation of NaCl in water produces 1 mol Na⁺ and 1 mole Cl⁻.
Total number of particles produced = 2
Osmolarity of solution = number of particles * molarity of siolution
Osmolarity = 2 * 5.64 * 10⁻⁷ mol/L = 1.128 osmol
e. mass of percent of NaCl = {mass of NaCl (g)/ mass of solution (g)} * 100
density of water = 1 Kg/L
mass of water = 1 Kg/L * 1000 L = 1000 kg
1Kg = 1000 g
Therefore mass of solution in g = 1000 * 1000 = 1 * 10⁶ g
mass percent of NaCl = (0.033/1 * 10⁶) * 100 = 3.30 * 10⁻⁶ %
f. Parts per million of NaCl:
parts per million = 1 mg of solute/L of solution
One thousandth of a gram is one milligram and 1000 ml is one liter, so that 1 ppm = 1 mg per liter = mg/Liter.
Since the density of water is 1kg/L = 1,000,000 mg/L
1mg/L = 1mg/1,000,000mg or one part in one million.
parts per million NaCl = 33.0/1000 L = 0.033 ppm NaCl
g. Parts per billion = 1 µg/L of solution
1 g = 1000 µg
therefore, 33.0 mg = 33.0 * 1000 µg = 3.30 * 10⁴ µg
parts per billion of NaCl = 3.30 * 10⁴ µg/1000 L = 33 ppb of NaCl
h. From the values obtained from e, f and g, the most convenient to use and understand is parts per billion as it has less of a fractional part to deal with especially since the solute concentration is very small.
A chemist prepares a solution of barium chlorate by measuring out of barium chlorate into a volumetric flask and filling the flask to the mark with water. Calculate the concentration in of the chemist's barium chlorate solution. Be sure your answer has the correct number of significant digits.
Complete Question
A chemist prepares a solution of barium chlorate BaClO32 by measuring out 42.g of barium chlorate into a 500.mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in /molL of the chemist's barium chlorate solution. Be sure your answer has the correct number of significant digits.
Answer:
The concentration is [tex]C = 0.28 \ mol/L[/tex]
Explanation:
From the question we told that
The mass of [tex]Ba(ClO_{3})_2[/tex] is [tex]m_b = 42 \ g[/tex]
The volume of the solution [tex]V_s = 500 mL = 500*10^{-3} L[/tex]
Now the number f moles of [tex]Ba(ClO_{3})_2[/tex] in the solution is mathematically represented as
[tex]n = \frac{m_b}{Z_b}[/tex]
Where [tex]Z_b[/tex] is the molar mass of [tex]Ba(ClO_{3})_2[/tex] which a constant with a value
[tex]Z_b = 304.23 \ g/mol[/tex]
Thus
[tex]n = \frac{42}{304.23}[/tex]
[tex]n = 0.14 \ mol[/tex]
The concentration of [tex]Ba(ClO_{3})_2[/tex] in the solution is mathematically evaluated as
[tex]C = \frac{n}{V_2}[/tex]
substituting values
[tex]C = \frac{0.14}{500*10^{-3}}[/tex]
[tex]C = 0.28 \ mol/L[/tex]
describe how would you use chromatography to show whether blue ink contains a single purple dye or a mixture of dyes
Explanation:
if the solution placed on the chromatography is pure there will be formation of one spot from the baseline and will go farthest to the front line unlike the impure one
With ink chromatography, a small amount of ink is added to the paper, one end is submerged in water, and the different colors of the ink are revealed as the water moves up the paper. All of this is made possible by the water base and variety of salabilities or densities that make up ink.
What is chromatography ?Separating mixture's constituent parts by chromatography is a method. The mixture is dissolved in a material known as the mobile phase to start the process, which then transports it through a material known as the stationary phase.
A little dot of the ink to be separated is placed at one end of a strip of filter paper to perform ink chromatography. The paper strip's opposite end is submerged in a solvent. The solvent moves up the paper strip, dissolving the chemical combination as it goes and pulling it up the paper.
Throughout the experiment, the dyes are pulled along by the mobile phase (water) as it gently advances up the stationary phase (paper).
Thus, With ink chromatography, a small amount of ink is added to the paper, one end is submerged in water.
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If one contraction cycle in muscle requires 55 kJ55 kJ , and the energy from the combustion of glucose is converted with an efficiency of 35%35% to contraction, how many contraction cycles could theoretically be fueled by the complete combustion of one mole of glucose? Round your answer to the nearest whole number.
Answer:
18 moles
Explanation:
Here the combustion of one mole of glucose ----> carbon dioxide + water, releases 2870 kilojoules / moles.
_______________________________________________________
With one contraction cycle requiring 55 kilojoules,
2870 / 55 ≈ 52.18
And with the efficiency being 35 percent,
52.1818..... * 0.35 = ( About ) 18 moles
Hope that helps!
How does the number of valence electrons in an atom relate to the element's
placement on the periodic table?
A. Elements in the same group have the same number of valence
electrons.
B. The number of valence electrons increases as the atomic number
increases.
O C. The number of valence electrons is the same for all elements on
the periodic table.
D. Elements in the same period have the same number of valence
electrons.
How many grams of POCl3 are produced when 225.0 grams of P4O10 and 675.0 grams of PCl5 react? This is the balance equation P4O10 + 6PCl5 → 10POCl3
Answer:
900g of POCl₃
Explanation:
Hello,
To solve this question, we'll require the equation of reaction.
P₄O₁₀ + 6PCl₅ → 10POCl₃
Molar mass of P₄O₁₀ = 283.886 g/mol
Molar mass of PCl₅ = 208.24 g/mol
Molar mass of POCl₃ = 153.33 g/mol
But Number of moles = mass / molar mass
Mass = molar mass × number of moles
Mass of POCl₃ = 153.33 × 10 = 1533.3g
Mass of PCl₅ = 208.24 × 6 = 1249.44g
Mass of P₄O₁₀ = 283.886 × 1 = 283.886g
From the equation of reaction,
283.886g of P₄O₁₀ + 1249.44g of PCl₅ produces 1533.33g of POCl₃
I.e 1533.33g of reactants produces 1533.33g of product (law of conservation of mass)
Therefore, (225g of P₄O₁₀ + 675g of PCl₅) = 900g will give x g of POCl₃.
1533.33g of reactants = 1533.33g of products
900g of reactants = x g of products
x = (900 × 1533.33) / 1533.33
x = 900g of POCl₃
an unknown metal of mass 512 g at a temperature of 15C is dropped into 325 g of water held in a 100 g aluminum container at the temperature of 98 c. is the system reaches thermal equilibrium at 78C determine th despicfic heat of the metal
Answer:
The specific heat capacity of the metal is 0.843J/g°C
Explanation:
Hello,
To determine the specific heat capacity of the metal, we have to work on the principle of heat loss by the metal is equals to heat gained by the water.
Heat gained by the metal = heat loss by water + calorimeter
Data,
Mass of metal (M1) = 512g
Mass of water (M2) = 325g
Initial temperature of the metal (T1) = 15°C
Initial temperature of water (T2) = 98°C
Final temperature of the mixture (T3) = 78°C
Specific heat capacity of metal (C1) = ?
Specific heat capacity of water (C2) = 4.184J/g°C
Heat loss = heat gain
M2C2(T2 - T3) = M1C1(T3 - T1)
325 × 4.184 × (98 - 78) = 512 × C1 × (78 - 15)
1359.8 × 20 = 512C1 × 63
27196 = 32256C1
C1 = 27196 / 32256
C1 = 0.843J/g°C
The specific heat capacity of the metal is 0.843J/g°C
The acetic acid/acetate buffer system is a common buffer used in the laboratory. Write the equilibrium equation for the acetic acid/acetate buffer system. The formula of acetic acid is CH3CO2H .
Answer:
CH₃CO₂H + H₂O ⇄ CH₃CO₂⁻ + H₃O⁺
Explanation:
A buffer is defined as the mixture of a weak acid and its conjugate base or vice versa.
For the acetic acid buffer, CH₃CO₂H is the weak acid and its conjugate base is the ion without H⁺, that is CH₃CO₂⁻. The equilibrium equation in water knowing this is:
CH₃CO₂H + H₂O ⇄ CH₃CO₂⁻ + H₃O⁺In the equilibrium, the acid is dissociated in the conjugate base and the hydronium ion.
The acetic acid/acetate buffer system is a common buffer used in the laboratory, the equilibrium equation for the acetic acid/acetate buffer system. The formula of acetic acid is CH3CO2H -
CH₃CO₂H + H₂O ⇄ CH₃CO₂⁻ + H₃O⁺
An acid buffer is a solution that contains roughly the same concentrations of a weak acid and its conjugate base.
an acetate buffer contains roughly equal concentrations of acetic acid and acetate ion.Both are in chemical equilibrium with each other.The equation is:
CH₃CO₂H + H₂O ⇄ CH₃CO₂⁻ + H₃O⁺
where CH₃CO₂H - acetic acid
and, CH₃CO₂⁻ acetate ion
Thus, CH₃CO₂H + H₂O ⇄ CH₃CO₂⁻ + H₃O⁺ is the equilibrium equation for the acetic acid/acetate buffer system.
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Air is compressed from an inlet condition of 100 kPa, 300 K to an exit pressure of 1000 kPa by an internally reversible compressor. Determine the compressor power per unit mass flow rate if the device is (a) isentropic, (b) polytropic with n =1.3, (c) isothermal
Answer:
(a) [tex]W_{isoentropic}=8.125\frac{kJ}{mol}[/tex]
(b) [tex]W_{polytropic}=7.579\frac{kJ}{mol}[/tex]
(c) [tex]W_{isothermal}=5.743\frac{kJ}{mol}[/tex]
Explanation:
Hello,
(a) In this case, since entropy remains unchanged, the constant [tex]k[/tex] should be computed for air as an ideal gas by:
[tex]\frac{R}{Cp_{air}}=1-\frac{1}{k} \\\\\frac{8.314}{29.11} =1-\frac{1}{k}\\[/tex]
[tex]0.2856=1-\frac{1}{k}\\\\k=1.4[/tex]
Next, we compute the final temperature:
[tex]T_2=T_1(\frac{p_2}{p_1} )^{1-1/k}=300K(\frac{1000kPa}{100kPa} )^{1-1/1.4}=579.21K[/tex]
Thus, the work is computed by:
[tex]W_{isoentropic}=\frac{kR(T_2-T_1)}{k-1} =\frac{1.4*8.314\frac{J}{mol*K}(579.21K-300K)}{1.4-1}\\\\W_{isoentropic}=8.125\frac{kJ}{mol}[/tex]
(b) In this case, since [tex]n[/tex] is given, we compute the final temperature as well:
[tex]T_2=T_1(\frac{p_2}{p_1} )^{1-1/n}=300K(\frac{1000kPa}{100kPa} )^{1-1/1.3}=510.38K[/tex]
And the isentropic work:
[tex]W_{polytropic}=\frac{nR(T_2-T_1)}{n-1} =\frac{1.3*8.314\frac{J}{mol*K}(510.38-300K)}{1.3-1}\\\\W_{polytropic}=7.579\frac{kJ}{mol}[/tex]
(c) Finally, for isothermal, final temperature is not required as it could be computed as:
[tex]W_{isothermal}=RTln(\frac{p_2}{p_1} )=8.314\frac{J}{mol*K}*300K*ln(\frac{1000kPa}{100kPa} ) \\\\W_{isothermal}=5.743\frac{kJ}{mol}[/tex]
Regards.
Which statements accurately describe the evidence that scientists gather using fossils? Check all that apply. The fossil record can be used to date rocks. Living things with many cells have always lived on Earth. Simple organisms are found only in young rocks. Geologists study ancient remains of plants and animals. Scientists can figure out what ancient living things ate. Pollen and seeds help provide clues about ancient climates.
Answer:
A, E, and F!
Explanation:
Evidence that was gathered by scientists through the use of Fossils among the given options are;
The fossil record can be used to date rocks.
Scientists can figure out what ancient living things ate.
Pollen and seeds help provide clues about ancient climates
Fossils can be regarded as remnants or traces that was left behind by things, organisms, animals that has once a living thing from the past. Examples of Fossils could be bones as well as shells and exoskeletons or stone, imprints of animals.Fossil record can be explained as compilation both the known and unknown fossils that exist over a period of time.Some evidence gathered by scientists through the use of Fossils helps to know that with fossil record the date rocks can be known and figuring out of foods that was eaten by ancient living things. With the Pollen and seeds, clues about ancient climates can be gottenWith the study of Fossils records, the scientist can tell the period of time that life has existed here on Earth. It also tells the relationship between plant and animals.
Therefore, options A F and E are required options.
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A 0.0372-m3 container is initially evacuated. Then, 4.65 g of water is placed in the container, and, after some time, all of the water evaporates. If the temperature of the water vapor is 368 K, what is its pressure
Answer:
18.3 kilopascals
Explanation:
We are given that the volume of this container is 0.0372 meters^3, that the mass of water is 4.65 grams, and that the temperature of this water vapor ( over time ) is 368 degrees Kelvins. This is a problem where the ideal gas law is an " ideal " application.
_______________________________________________________
First calculate the number of moles present in the water ( H2O ). Water has a mass of 18, so it should be that n, in the ideal gas law - PV = nRT, is equal to 4 / 18. It is the amount of the substance.
We now have enough information to solve for P in PV = nRT,
P( 0.0372 ) = 4 / 18( 8.314 )( 368 ),
P ≈ 18,276.9
Pressure ≈ 18.3 kilopascals
Hope that helps!
Why does a chemical change occur when copper is heated?
Answer:
When copper is heated, it decomposes to form copper oxide and carbon dioxide. It is an endothermic reaction, which means that it absorbs heat. When heated, copper is easily bent or molded into shapes.
Explanation:
What are the concentrations of Cu2+, NH3, and Cu(NH3)42+ at equilibrium when 18.8 g of Cu(NO3)2 is added to 1.0 L of a 0.800 M solution of aqueous ammonia? Assume that there is no volume change upon the addition of the solid, and that the reaction goes to completion and forms Cu(NH3)42+.
Answer:
Explanation:
Cu(NO₃)₂ + 4NH₃ = Cu(NH₃)₄²⁺ + 2 NO₃⁻
187.5 gm 4M 1 M
187.5 gm reacts with 4 M ammonia
18.8 g reacts with .4 M ammonia
ammonia remaining left after reaction
= .8 M - .4 M = .4 M .
187.5 gm reacts with 4 M ammonia to form 1 M Cu(NH₃)₄²⁺
18.8 g reacts with .4 M ammonia to form 0.1 M Cu(NH₃)₄²⁺
At equilibrium , the concentration of Cu²⁺ will be zero .
concentration of ammonia will be .4 M
concentration of Cu(NH₃)₄²⁺ formed will be 0.1 M
Five solutions on how to prevent air pollution
Answer:
Reduce number of trips
Avoid burning leaves
Avoid using garden equipments
Reduce the use of wood stove
Avoid gas-powered lawn.
Explanation:
Why need to add NaAlF6 to Al2O3?
A protein's secondary structure arises due to interactions between amino acids. Two common secondary structures found in many proteins are alpha helices and beta sheets. Classify the following statements as pertaining to alpha helices or beta sheets.
1. Keep their shape due to hydrogen bonds between adjacent polypeptides chains
2. form long thin structures important for transmembrane proteins
3. flat zig zag like structure
4. a rigid spring like structure around a central axis
Answer:
Alpha helixes:
- form long thin structures important for transmembrane proteins
- have a rigid spring like structure around a central axis
Beta sheets:
- Keep their shape due to hydrogen bonds between adjacent polypeptides chains
- have a flat zig zag like structure
Explanation:
Alpha helices and beta pleated sheets are two types of secondary structure found in proteins.
Alpha helix: In this structure, the polypeptide backbone is tightly wound around an imaginary central axis drawn longitudinally through the center with the R groups of the amino acids protruding outward from the helical backbone. This structure looks like a spring and could either be a left-handed or right-handed helix, though the left-handed helix has not been observed in proteins. Each turn of the helix includes about 3.6 amino acid residues.
The alpha helix is stabilized by a hydrogen bond between the hydrogen atom attached to the electronegative nitrogen atom of a peptide linkage and the electronegative carbonyl oxygen atom of the fourth amino acid on the amino-terminal side of that peptide bond.
Alpha-helices due to their structure, are the most common transmembrane proteins- protein structure element that crosses biological membranes.
Beta sheets: In the beta conformation, the backbone of the polypeptide chain is extended into a zigzag structure. The zigzag polypeptide chain can be arranged side by side to form a structure resembling a series of pleats known as beta sheets. Hydrogen bonds formed between adjacent segments of the polypeptide chain functions to stabilize the structure.
The beta comformation in the form of turns is common in globular proteins.
Where are valence electrons located in an atom?
A. In all energy levels
B. In the outermost energy level
C. In the lowest energy level
D. In the nucleus
Answer:
B.
Explanation:
Valence electrons located in the outermost energy level.
how many grams are there in 9.4x10^25 molecules of H2
Answer:
You start with 9.4 x 1025 molecules of H2.
You know that an Avogadro's number of molecules of H2 has a mass of 2.0 g.
To solve, 9.4 x 1025 molecules H2 x (2.0 g H2 / 6.023 x 1023 molecules H2) = 312. g H2
Explanation:
Above 882oC, zirconium has a BCC crystal structure with a = 0.332 nm. Below this temperature, zirconium has an HCP structure with a = 0.2978 nm and c = 0.4735 nm. Determine the percent volume change when BCC zirconium transforms to HCP zirconium. Is that contraction or expansion?
Answer:
[tex]\mathbf{\Delta V = -0.63 \%}[/tex]
Contraction
Explanation:
From the given information;
Above 88° C
zirconium has a BCC crystal structure with a = 0.332 nm
Below this temperature
zirconium has an HCP structure with a = 0.2978 nm and c = 0.4735 nm
the volume of BCC can now be:
[tex]V_{BCC} = (a)^3[/tex]
[tex]V_{BCC} = (0.332 \ nm)^3[/tex]
[tex]V_{BCC} =0.03660 \ nm^3[/tex]
the volume of HCP can now be:
[tex]V_{HCP} = (a)^2 (c) cos \ 30^0[/tex]
[tex]V_{HCP} = (0.2978)^2 (0.4735) \ cos 30[/tex]
[tex]V_{HCP} =0.03637 \ nm^3[/tex]
Ths; the volume percent change when BCC zirconium transforms to HCP zirconium can be calculated as:
[tex]\Delta V = \dfrac{V_{HCP}-V_{BCC}}{V_{BCC}} * 100 \%[/tex]
[tex]\Delta V = \dfrac{0.03637 \ nm^3-0.03660\ nm^3}{0.03660\ nm^3}} * 100 \%[/tex]
[tex]\mathbf{\Delta V = -0.63 \%}[/tex]
Hence; it is contraction due to what the negative sign portray, The negative sign signifies that there is contraction during cooling
During the winter months, many locations experience snow and ice storms. It is a common practice to treat roadways and sidewalks with salt, such as NaCl . If a 11.3 kg bag of NaCl is used to treat the sidewalk, how many moles of NaCl does this bag contain
Answer:The moles of NaCL in the 11.3kg bag is 193.36moles
Explanation:
Given that a bag of NaCl = 11.3kg
1kg = 1000g
therefore 11.3 kg = 11,300g
Remember that
No of moles = mass of subatance/ molar mass of substance
The molar mass of NaCl = Na + Cl= 22.989769 + 35.453 =58.442769≈ 58.44g/mol
No of moles = mass of subatance/ molar mass of substance
= 11300g/ 58.44g/mol = 193.36 moles
The moles of NaCL in the 11.3kg bag is 193.36 moles.
Determine the quantity (g) of pure MgSO4 in 2.4 g of MgSO4•7H2O. Show your work.
Answer: The quantity of pure [tex]MgSO_4[/tex] in 2.4 g of [tex]MgSO_4.7H_2O[/tex] is 1.17 g
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
To calculate the moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar Mass}}=\frac{2.4g}{246g/mol}=0.0098moles[/tex]
As 1 mole of [tex]MgSO_4.7H_2O[/tex] contains = 1 mole of [tex]MgSO_4[/tex]
Thus 0.0098 moles of [tex]MgSO_4.7H_2O[/tex] contains = [tex]\frac{1}{1}\times 0.0098=0.0098mole[/tex] of [tex]MgSO_4[/tex]
Mass of [tex]MgSO_4=0.0098mol\times 120g/mol=1.17g[/tex]
Thus the quantity of pure [tex]MgSO_4[/tex] in 2.4 g of [tex]MgSO_4.7H_2O[/tex] is 1.17 g