Answer:
THE NEW VOLUME OF THE GAS IS 3.124 L
Explanation:
Initial Temperature = 27°C = 27 + 273 K = 300 K
Pressure = constant
Initial Volume = 3.3 L
Final Temperature = 11 °C = 11+ 273 K = 284 K
Final volume = unknown
Using Charles' law, at constant pressure, the volume of a given gas is directly proportional to the temperature.
Mathematically,
V1 / T1 = V2 / T2
Re-arranging the formula by making V2 the subject of the formula
V2 = V1 T2 / T1
V2 = 3.3 * 284 / 300
V2 = 3.124 L
The new volume of the gas is therefore 3.124 L at 11°C
The new volume is 3.1 L
The parameters given in the question are
T1= 27°c
convert to kelvin
= 273 + 27
= 300k
T2= 11°c
convert to kelvin
= 273+11
= 284k
Volume 1= 3.3 L
V1/T1= V2/T2
3.3/300= V2/284
Cross multiply
284×3.3= 300×V2
937.2= 300V2
V2= 937.2/300
= 3.1
Hence the new volume is 3.1 L
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If 8.23 g of magnesium chloride react completely with sodium phosphate, how many grams of magnesium phosphateare produced
Answer:
The correct answer is 7.57 grams of magnesium phosphate.
Explanation:
Based on the given question, the chemical reaction taking place is:
2Na₃PO₄ (aq) + 3MgCl₂ (aq) ⇒ Mg₃(PO₄)2 (s) + 6NaCl (aq)
From the given reaction, it is evident that two moles of sodium phosphate reacts with three moles of magnesium chloride to produce one mole of magnesium phosphate.
Based on the given information, 8.23 grams of magnesium chloride reacts completely with sodium phosphate, therefore, magnesium chloride in the given case is the limiting reagent.
In the given case, 3 moles of magnesium chloride produce 1 mole of magnesium phosphate. Therefore, 1 mole of magnesium chloride will produce 1/3 mole of magnesium phosphate.
The molecular mass of magnesium chloride is 95.21 grams per mole. So, 1 mole of magnesium chloride is equivalent to 95.21 grams of magnesium chloride.
On the other hand, the molecular mass of magnesium phosphate is 262.85 grams per mole. Therefore, 1 mole of magnesium phosphate is equal to 262.85 grams of magnesium phosphate.
As seen earlier that 1 mole of magnesium chloride = 1/3 moles of magnesium phosphate. So,
95.21 grams of magnesium chloride = 1/3 × 262.85 grams of magnesium phosphate
= 262.85 / 3 grams of magnesium phosphate
1 gram of magnesium chloride = 262.85 / 3 × 95.21 grams of magnesium phosphate
8.23 grams of magnesium chloride = 262.85 / 3 × 95.21 × 8.23 grams of magnesium phosphate
= 7.57 grams of magnesium phosphate
Hence, when 8.23 grams of magnesium chloride when reacts completely with sodium phosphate, it produces 7.57 grams of magnesium phosphate.
Dinitrophenol (DNP) is a drug that has the ability to separate the flow of electrons through the
electron transport and ATP proton pumps, used during the electron transport system. This
means that the energy from electron transfer cannot be used for ATP synthesis. Assuming
your bacteria has consumed DNP, how many ATPs would they produce form the complete,
aerobic oxidation of one glucose molecule?
Answer:
Four
Explanation:
Glycolysis ⟶ 2ATP
TCA cycle ⟶ 2ATP
ETC ⟶ 34ATP
Total = 38ATP
DNP disrupts the electron transport chain, so the bacteria will produce only four molecules of ATP from one of glucose.
Calculate the mass percent by volume of 330.1 g of glucose (C₆H₁₂O₆, MM = 180.2 g/mol) in 325 mL of solution.
Answer: The mass percent by volume is 101.6%
Explanation:
The solution concentration expressed in percent by volume means that the amount of solute present in 100 parts volume of solution.
It is represented in formula as :
mass percent by volume =[tex]\frac{\text {mass of solute}\times 100}{\text {Volume of solution in ml}}\%[/tex]
Given : mass of glucose = 330.1 g
volume of solution = 325 ml
Thus mass percent by volume =[tex]\frac{330.1g\times 100}{325ml}=101.6\%[/tex]
Thus the mass percent by volume is 101.6%
The process by which the movement of internal bonds converts one type of what organic compound into another is
Answer: It's is called Reaarrangement
Explanation:
Rearrangement is a chemic reaction in which an atom or group of atoms bond migrate from one carbon atom to another. The movement involves two adjacent atoms and move over a large distance. It is important in functional group transformation.
Reaarrangement can be classified based on the atom or group of atoms it migrate.
Nucleophilic rearrangement which involves the migration of atoms with electron pairs.
Electrophilic migration involved the migration of atom or groups without electron pair.
Free radical involves the atom or group of atoms moving with a lone pair of electron.
g The "Coulomb barrier" is defined to be the electric potential energy of a system of two nuclei when their surfaces barely touch. The probability of a nuclear reaction greatly increases if the energy of the system is above this barrier. What is the Coloumb barrier (in MeV) for the absorption of an alpha particle by a lead-208 nucleus
Answer:
The Coulomb Barrier U is 25.91 MeV
Explanation:
Given that:
Atomic Mass of lead nucleus A = 208
atomic mass of an alpha particle A = 4
Radius of an alpha particle [tex]R_\alpha = R_o A^{^{\dfrac{1}{3}}[/tex]
where;
[tex]R_\alpha = 1.2 \times 10 ^{-15} \ m[/tex]
[tex]R_\alpha = R_o A^{^{\dfrac{1}{3}}[/tex]
[tex]R_\alpha = 1.2 \times 10 ^{-15} \ m \times (4) ^{^{\dfrac{1}{3}}[/tex]
[tex]R_\alpha = 1.905 \times 10^{-15} \ m[/tex]
Radius of the Gold nucleus
[tex]R_{Au}= R_o A^{^{\dfrac{1}{3}}[/tex]
[tex]R_{Au}= 1.2 \times 10 ^{-15} \ m \times (208) ^{^{\dfrac{1}{3}}[/tex]
[tex]R_{Au} = 7.11 \times 10^{-15} \ m[/tex]
[tex]R = R_\alpha + R_{Au}[/tex]
[tex]R = 1.905 \times 10^{-15} \ m + 7.11 \times 10^{-15} \ m[/tex]
[tex]R = 9.105 \times 10 ^{-15} \ m[/tex]
The electric potential energy of the Coulomb barrier [tex]U = \dfrac{Ke \ q_{\alpha} q_{Au}}{R}[/tex]
[tex]U = \dfrac{8.99 \times 10^9 \ N.m \ ^2/C ^2 \ \times 2 ( 82) \times \(1.60 \times 10^{-19} C \ \ e } {9.105 \times 10^{-15} \ m }[/tex]
U = 25908577.7eV
U = 25.908577 × 10⁶ eV
U = 25.91 MeV
The Coulomb Barrier U is 25.91 MeV
2 Points
Which element has the fewest valence electrons?
A. Magnesium (Mg)
B. Neon (Ne)
C. Chlorine (CI)
O D. Silicon (Si)
SUSNE
Answer:
A. Magnesium (Mg)Explanation:
As the elements go left in the periodic table, they have fewer valence electrons.
Magnesium has 2 valence electrons.
Neon has 8 valence electrons.
Chorine has 7 valence electrons.
Silicon has 4 valence electrons.
Magnesium has the fewest valence electrons.
Answer:
A
Explanation:
Magnesium
How much heat is absorbed when 52.39 H2O(l) at 100°C and 101.3 kPa is converted to steam at 100°C? (The molar heat of vaporization of water is
40.7 k/mol.)
2.09 x 1020
O 2.31% 10110
O 1.18 x 102 103
O 1.11% 1021)
The element nitrogen would be expected to form covalent bond(s) in order to obey the octet rule. Use the octet rule to predict the formula of the compound that would form between nitrogen and hydrogen , if the molecule contains only one nitrogen atom and only single bonds are formed. Formula:
Answer:
The compound formula will be "NF₃". The further explanation is given below.
Explanation:
Nitrogen seems to have an electrical structure consisting of 1S², 2S² as well as 3S² and it requires three electrons to fulfill or conclude the octet. This will, therefore, form three bonds (covalent). Even though only single nitrogen has been present, that can only represent a single bond including fluorine. Therefore the methodology for something like the compound would be NF₃.So that the above would be the right answer.
Question 39 (1 point)
What is the volume (in L) of 4.20 grams of CO2 gas at STP? (
molar masses are,
Carbon = 12.01 g/mol, and oxygen - 16.00 g/mol)
Your Answer:
Answer:
volume = 2128L
Explanation:
volume at stp = 22.4dm³ =22400L
CO2 = 12 + 2(16) = 44
4.20/44 = volume/22400L
0.095 = volume/22400L
volume = 0.095 x 22400
volume = 2128L
Calculate the volume of 0.500 M C2H3O2H and 0.500 M C2H3O2Na required to prepare 0.100 L of pH 5.00 buffer with a buffer strength of 0.100 M. The pKa of C2H3O2H is 4.75.
Answer:
You require 12.8mL of the 0.500M C₂H₃O₂Na and 7.2mL of the 0.500M C₂H₃O₂H
Explanation:
It is possible to obtain pH of a weak acid using H-H equation:
pH = pKa + log₁₀ [A⁻] / [HA]
For the buffer of acetic acid/acetate, the equation is:
pH = pKa + log₁₀ [C₂H₃O₂Na] / [C₂H₃O₂H]
Replacing:
5.00 = 4.75 + log₁₀ [C₂H₃O₂Na] / [C₂H₃O₂H]
1.7783 = [C₂H₃O₂Na] / [C₂H₃O₂H] (1)
Buffer strength is the concentration of the buffer, that means:
0.1M = [C₂H₃O₂Na] + [C₂H₃O₂H] (2)
Replacing (2) in (1):
1.7783 = 0.1M - [C₂H₃O₂H] / [C₂H₃O₂H]
1.7783 [C₂H₃O₂H] = 0.1M - [C₂H₃O₂H]
2.7783 [C₂H₃O₂H] = 0.1M
[C₂H₃O₂H] = 0.036MAlso:
[C₂H₃O₂Na] = 0.1M - 0.036M
[C₂H₃O₂Na] = 0.064MThe moles of both compounds you require is:
[C₂H₃O₂Na] = 0.1L × (0.064mol / L) = 0.0064moles
[C₂H₃O₂H] = 0.1L × (0.036mol / L) = 0.0036moles
Your stock solutions are 0.500M, thus, volume of both solutions you require is:
[C₂H₃O₂Na] = 0.0064moles × (1L / 0.500M) = 0.0128L = 12.8mL
[C₂H₃O₂H] = 0.0036moles × (1L / 0.500M) = 0.0072mL = 7.2mL
You require 12.8mL of the 0.500M C₂H₃O₂Na and 7.2mL of the 0.500M C₂H₃O₂Hg what would happen to the solubility of a gas in a solution if the pressure above the solution is increased
Answer: The solubility of gas increases in a solution if the pressure above the solution is increased
Explanation:
Henry's law states that the amount of gas dissolved or molar solubility of gas is directly proportional to the partial pressure of the liquid.
To calculate the molar solubility, we use the equation given by Henry's law, which is:
[tex]C=K_H\times p[/tex]
where,
C = solubility
[tex]K_H[/tex] = Henry's constant
p = partial pressure
As the solubility is directly proportional to the pressure, thus increasing the pressure increases the solubility.
Five mol of calcium carbide are combined with 10 mol of water in a closed, rigid, high-pressure vessel of 1800 cm3 internal empty volume. Acetylene gas is produced by the reaction:
Answer:
CaC₂ + 2H₂O → C₂H₂ + Ca(OH)₂
Explanation:
In order to find out the reaction, we must know the reactants.
For this situation, we make acetylene gas from carbide calcium CaC₂ and H₂O (water); therefore the reactants are:
- CaC₂ and H₂O
Acetylene is one of the products made → C₂H₂
So the reaction can be formed as this: CaC₂ + H₂O → C₂H₂
We missed the calcium, and this reaction also makes, Calcium Hydroxide, so the complete equation must be:
CaC₂ + H₂O → C₂H₂ + Ca(OH)₂
This is unbalanced, because we have 1 O in left side and 2 in right side so we add 2 in water so now, we get the complete reaction:
1 mol of calcium carbide reacts to 2 mol of water in order to produce 1 mol of acetylene and 1 mol of calcium hydroxide.
Using the determined equivalence point from question 2 and the balanced reaction of acetic acid and sodium hydroxide, calculate the molarity of the acetic acid in your hot sauce packet.
Equivalance point is 3.0 mL NaOH, 0.6 g hot sauce, 0.1 M NaoH.
Answer:
Molarity of the packet is 0.5M
Explanation:
In the reaction of acetic acid with NaOH:
CH₃COOH + NaOH → CH₃COO⁻ + H₂O + Na⁺
1 mole of acetic acid reacts with 1 mole of NaOH.
When you are titrating the acid with NaOH, you reach equivalence point when moles of acid = moles of NaOH.
Moles of NaOH are:
3.0mL = 3.0x10⁻³L ₓ (0.1 mol / L) = 3.0x10⁻⁴ moles of NaOH = moles of CH₃COOH.
Now, you find the moles of acetic acid in the hot sauce packet. But molarity is the ratio between moles of the acid and liters of solution.
As you don't know the volume of your packet, you can assume its density as 1g/mL. Thus, volume of 0.6g of hot sauce is 0.6mL = 6x10⁻⁴L.
And molarity of the packet is:
3.0x10⁻⁴ moles acetic acid / 6x10⁻⁴L =
0.5MFor the reaction Ca(s)+Cl2(g)→CaCl2(s) calculate how many grams of the product form when 14.4 g of Ca completely reacts. Assume that there is more than enough of the other reactant.
Answer:
[tex]m_{CaCl_2}=39.96gCaCl_2[/tex]
Explanation:
Hello,
In this case, for the undergoing reaction, we can compute the grams of the formed calcium chloride by noticing the 1:1 molar ratio between calcium and it (stoichiometric coefficients) and using their molar mass of 40 g/mol and 111 g/mol by using the following stoichiometric process:
[tex]m_{CaCl_2}=14.4gCa*\frac{1molCa}{40gCa} *\frac{1molCaCl_2}{1molCa} *\frac{111gCaCl_2}{1molCaCl_2}\\ \\m_{CaCl_2}=39.96gCaCl_2[/tex]
Clearly, chlorine is not used since it is said there is enough for the reaction to go to completion.
Best regards.
You need to purify 2.0 grams of an impure sample of Acetanilide. The sample is contaminated with aniline. After the purification is complete you isolate 0.8 grams of acetanilide and record a melting point range of 108-110 °C. Complete the following calculations and show your work.
a. Calculate the minimum amount of distilled water you would use to complete the recrystallization.
b. How much acetanilide will still be dissolved in solution even after the sample is cooled to 0 °C?
c. Calculate the % recovery and the % error for the melting point.
d. Why is the percent recovery less than 100%? Describe multiple sources for loss of sample.
Answer:
Following are the answer to this question:
Explanation:
In the given question an attachment file is missing, that is attached. please find the attached file, and the following are the description of the given points:
a. At 100 degrees in 100 mL 5 g is dissolved.
For, it required:
[tex]\to 2g = 100 \times \frac{2}{5}[/tex]
[tex]= 40 \ \ ml \ of \ water.[/tex]
b. At 0 degrees 100 mL dissolve in 0.3 g.
So, the dissolve:
[tex]\to 40 \ ml= 0.3\times \frac{40}{100}[/tex]
[tex]= 0.12g.[/tex]
After refrigeration 0.12 g will still be dissolved.
c. After dissolving and freezing, precipitation can occur which would still be impure if the cooling is instantaneous. The added solvent was also too hard to recrystallize. The solvent was placed below its place of reservation.
d. Recovery percentage:
[tex]\to \frac{0.8}{2}\times100[/tex]
[tex]\to 40 \ \%[/tex]
The melting point of acetanilide:
[tex]\to 114.3^{\circ}.[/tex]
Found=109(medium)
Melting point error percentages:
[tex]= \frac{114.3-109}{114.3}\\\\=4.63 \ \%[/tex]
a. If the temperature change of the dissolution of urea from your experiment were determined much lower than the actual temperature change, What is the effect on the value of entropy calculated from the incorrect data?
Explanation:
Before proceeding, we have to first understand the relationship between temperature and entropy.
From the equation of entropy which is given as;
ΔS = ΔQ / T
We can tell that entropy is inversely proportional to temperature.
This means that at constant heat, as the temperature increases, the entropy decreases and vice versa.
Inn this question, the temperature is much lower - a decrease. The effect that this would have on the value of the entropy is that it would be increased. A higher value of entropy would be recorded than the actual value of the entropy.
Calculate the mass in grams for 0.251 moles of Na2CO3
Answer:
Explanation:
the molar mass for Na2CO3 is 2*23+12+3*16=106 g/mole
106*0.251=26.606 grames
Identify the ions in the compounds represented in the following formulas. Click in the answer box to open the symbol palette.
Cation Formula Anion Formula
a) NaBr
b) AlCI3
c) Ba3(PO42
d) Mn(NO3)2
Answer and Explanation:
A ionic compound can be dissociated into its ions: cations (with positive charge) and anions (with negative charge). The net charge of the compound is zero, so the sum of the charges of the ions must be zero.
We can see the ions in the compounds from the dissociation equilibrium, as follows:
a) NaBr ⇒ Na⁺ + Br⁻
Cation: Na⁺
Anion: Br⁻ (bromide)
b) AlCI₃ ⇒ Al³⁺ + 3 Cl⁻
Cation: Al³⁺
Anion: Cl⁻ (chloride)
c) Ba₃(PO₄)₂⇒ 3 Ba²⁺ + 2 PO₄³⁻
Cation: Ba²⁺
Anion: PO₄³⁻ (phosphate)
d) Mn(NO₃)₂ ⇒ Mn²⁺ + 2 NO₃⁻
Cation: Mn²⁺
Anion: NO₃⁻ (nitrate)
If iron metal reacts with an aqueous solution of silver nitrate and zinc reacts with an aqueous solution of iron sulfate, rank these three metals Fe Zn Ag in order of decreasing reactivity.
Answer:
yes!you are right a cloudy formation will be formed when they will react.its because if nitrogen.
Organic chemistry too eazy but why 90% students avoid ?
Answer:
because it covers a large area as there are more then 1 lakh compounds of organic chemistry.
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
Answer:
Maximum mass of compound produced = 64 Kg
Explanation:
Carbon monoxide react with hydrogen to produce methanol. Equation for the reaction is given as follows:
CO(g) + 2H₂(g) -----> CH₃OH(l)
From the equation of reaction, 1 mole of CO reacts with 2 moles of Hydrogen gas to produce 1 mole of methanol.
Molar mass of CO = 28 g
Molar mass of H₂ = 2 g
Molar mass of methanol = 32 g
Therefore, 28 g of CO reacts with 4 g of H₂ to produce 32 g of methanol
8.0 Kg of hydrogen will react with 8 * (28/4) Kg of CO = 56 Kg of CO.
therefore, hydrogen is the limiting reactant in the reaction under consideration.
8.0 Kg of Hydrogen will react with 56 Kg of CO to produce 8 * (32/4) Kg of methanol = 64 Kg of methanol
Therefore, maximum mass of compound produced = 64 Kg
How much MnO2(s) should be added to excess HCl(aq) to obtain 195 mL Cl2(g) at 25 °C and 715 Torr g
THIS IS THE COMPLETE QUESTION
Chlorine can be prepared in the laboratory by the reaction of manganese dioxide with hydrochloric acid, HCl(aq), as described by the chemical equation.
How much MnO2(s) should be added to excess HCl(aq) to obtain 185 mL of Cl2(g) at 25 °C and 715 Torr?
Answer:
0.62901mol of MnO2(s) should be added
Explanation:
Given:
P = 715/760 = 0.94078atm
v=195ml=0.195l
n = ? moles have to find
R = 0.0821 L atm/K/mole
T = 25 + 273 = 298 K
Then we will make use of below formula
PV = nRT
Insert the values
0.94078*0.195=n 0.0821*298
24.466n=0.1740443
n=0.174/24.466
n=0.007235 nb of moles of cl2
as 1 mole of Cl2 were obtained from 1 mole of MnO2
so 0.007235 of chlorine must have come from
0.007235 moles of MnO2
1 mole of MnO2 = 86.94 g/mole
so 0.007235 moles of MnO2== 86.94* 0.007235
=0.62901
Which statements correctly describe the effect of distance in determining the gravitational force and the electrical force? Check all that apply.
Answer:
The gravitational force is inversely proportional to the square of the distance..
The electrical force is inversely proportional to the square of the distance..
Explanation:
From the Newton's law of universal gravity, we understood that the force of attraction between the masses two objects is inversely proportional to the square of the distance apart. Mathematically, it is expressed as:
F = GM1M2/r²
Where:
M1 and M2 are the masses of two objects measured in kilograms (Kg).
G is the gravitational constant with a value of 6.67×10¯¹¹ Nm²/Kg²
r is the distance apart measured in metre (m).
F is the force of attraction measured in Newton (N).
From the equation:
F = GM1M2/r²
The force (F) is inversely proportional to the square of the distance (r) apart. This means that the greater the distance apart, the smaller the force of attraction and the smaller the distance apart, the greater the force of attraction between the masses of the object.
From Coulomb's Law, we understood that the force of attraction between two charged particles is inversely proportional to square of the distance. Mathematically, it expreessed as
F = Kq1q2/ r²
Where:
q1 and q2 are charges of two objects measured in coulomb (C) .
r is the distance apart measured in metre (m)
K is the electrostatic constant with a value of 9×10^9 Nm²/C²
F is the force measured in Newton (N).
From the equation:
F = Kq1q2/ r²
The force (F) is inversely proportional to the square of the distance (r) apart.. This implies that as the distance between the charged particles increase, the smaller the force of attraction between them and as the distance between the charged particles decrease, the greater the force of attraction between the two charged particles.
Answer:
3 and 6
Explanation:
Which of the following is an inorganic compound?
Na4C
C2H6
C12H22O11
CH3COOH
Answer:
The answer is option A.
Na4C
Hope this helps you
Sort the resources into the correct categories.
are replaced by natural processes
Renewable Resources
Nonrenewable Resources
cannot be replaced in a short time
are used more quickly than replaced
have fixed amounts
are considered unlimited
are replaced faster than used
Intro
✓ Done
Answer:
Renewable Resources: are considered unlimited, are replaced faster than used.
Nonrenewable Resources: are used more quickly than replaced, have fixed amounts, cannot be replaced in a short time.
Explanation:
Renewable resources are natural resources that are able to naturally regenerate themselves, hence, they are considered to be unlimited. They are usually replaced faster than they are used because they have a short regeneration time. A good example is the solar energy.
Nonrenewable resources are those natural resources that cannot naturally regenerate and when they do, it takes a very long time (usually millions of years). They are therefore used at a much faster rate than they are being replaced and their natural deposits are more or less fixed due to the long regeneration time. A good example is the crude oil deposit.
Hence:
Renewable Resources: are considered unlimited, are replaced faster than used.
Nonrenewable Resources: are used more quickly than replaced, have fixed amounts, cannot be replaced in a short time.
Answer: !
Explanation:
NH4NO2(s)→N2(g)+H2O(l) ---------------- Express your answer as a chemical equation. Identify all of the phases in your answer.
Answer:
The balanced equation is :
NH4NO2(solid) = N2(gas) + 2 H2O(liquid)
Explanation:
A balanced chemical equation is an equation that has an equal number of atoms and charges on both sides of the equation. The given equation in question is imbalanced as the number of atoms not equal.
In this reaction, solid ammonium nitrite breaks into nitrogen gas and water, reaction known as decomposition.
The correct and balanced equation as follows :
NH4NO2(s) = N2(g) + 2 H2O(l)
A fictional cubed-shaped bacterium, Bacterius cubis, occupies a volume of 2.0 femtoliters. This particular type of bacteria is known to communicate with its own species by secreting a small molecule called bactoX ( MW=126.9 g/mol ). A. Each bacterium contains 7140 bactoX molecules that can be secreted. How many moles of bactoX are present in a 3.0 μL sample volume that contains 7.512×106 bacterial cells?
Answer:
There are [tex]\mathbf{8.90172 \times 10^{-14}}[/tex] moles of bactoX present in a 3.0 μL sample volume that contains 7.512×106 bacterial cells
Explanation:
Given that:
The number of molecules present in one bacterial cell is [tex]7.140 \times 10^3[/tex] molecules
and the sample contains [tex]7.512 \times 10^6[/tex] molecules.
Number of moles = number of molecules /Avogadro's number
where;
Avogadro's number = 6.023 × 10²³
Number of moles = [tex]\dfrac{7.140 \times 10^3}{6.023 \times 10^{23}}[/tex]
Number of moles = [tex]1.185 \times 10^{-20}[/tex] moles
So; [tex]1.185 \times 10^{-20}[/tex] moles is present in one bacteria cell
Similarly; the sample contains [tex]7.512 \times 10^6[/tex] molecules.
Therefore; the number of moles present in the bactoX is = [tex]1.185 \times 10^{-20} \times 7.512 \times 10^6[/tex]
= [tex]\mathbf{8.90172 \times 10^{-14}}[/tex] moles
➔ Which compound has both ionic and covalent bonds? A. Ammonium chloride B. Carbon dioxide C. Ethyl ethanoate D. Sodium chloride
Answer:
Choice A. Ammonium chloride.
Explanation:
Consider the bonds in each of the four compounds.
Ammonium chlorideAmmonium chloride [tex]\rm NH_4Cl[/tex] is an ionic compound. Each
The [tex]\rm {NH_4}^{+}[/tex] and [tex]\rm Cl^{-}[/tex] ions in [tex]\rm NH_4Cl[/tex] are connected with ionic bonds.
What make [tex]\rm NH_4Cl[/tex] special is that its cation [tex]\rm {NH_4}^{+}[/tex] is polyatomic. In other words, each [tex]\rm {NH_4}^{+}[/tex] ion contains more than one atoms. These atoms (one [tex]\rm N[/tex] atom and four [tex]\rm H[/tex] atoms) are connected with covalent bonds. Therefore, [tex]\rm NH_4Cl[/tex] has both ionic and covalent bonds.
Carbon dioxideCarbon dioxide [tex]\rm CO_2[/tex] is a covalent compound. Each [tex]\rm CO_2[/tex] molecule contains two [tex]\rm C=O[/tex] double bonds in total. [tex]\rm CO_2[/tex] molecules have no ionic bond.
Ethyl ethanoateThe name "ethyl ethanoate" might sound like the name of a salt (think about sodium ethanoate.) However, in reality, ethyl ethanoate [tex]\rm CH_3COOCH_2CH3[/tex] is an ester. The "ethyl" here refers to the [tex]\rm -OCH_2CH3[/tex] part, originating from ethanol. On the other hand, "ethanoate" refers to the [tex]\rm CH_3C(O)-[/tex] part, which can be obtained from ethanoic acid.
These two parts are connected with a covalent [tex]\rm C-O[/tex] single bond. (The [tex]\rm C[/tex] in ethanoic acid is connected to the [tex]\rm O[/tex] in ethanol.) As a result, there's no ionic bond in ethyl ethanoate, either.
Sodium chlorideSodium chloride [tex]\rm NaCl[/tex] is an ionic compound. Both the [tex]\rm Na^{+}[/tex] ion and the [tex]\rm Cl^{-}[/tex] are monoatomic. While the [tex]\rm Na^{+}[/tex] and [tex]\rm Cl^{-}[/tex] in sodium chloride are connected with ionic bonds, neither [tex]\rm Na^{+}[/tex] nor [tex]\rm Cl^{-}[/tex] contains covalent bond.
2. Write the chemical equations for the neutralization reactions that occurred when HCL and NaOH were added to the buffer solution.
Answer:
HCI(aq)+CH3COONa(s) ----> CH3COOH(aq)+NaCl(s)
NaOH(aq)+CH3COOH(aq) ----> CH3COONa(s)+H2O(l)
Explanation:
A buffer is a solution that resists changes in acidity or alkalinity. A buffer is able to neutralize a little amount of acid or base thereby maintaining the pH of the system at a steady value.
A buffer may be an aqueous solution of a weak acid and its conjugate base or a weak base and its conjugate acid.
The equations for the neutralizations that occurred upon addition of HCl or NaOH are;
HCI(aq)+CH3COONa(s) ----> CH3COOH(aq)+NaCl(s)
NaOH(aq)+CH3COOH(aq) ----> CH3COONa(s)+H2O(l)
Paper is stable at room temperature in the presence of oxygen (O2) because it requires ____________ to start the reaction.
Answer:
Energy
Explanation:
Paper is oxidized in the presence of oxygen. This reaction however proceeds very slowly until energy is supplied to the system. This implies that the reaction is not spontaneous at room temperature. A spontaneous reaction takes place without any need for external supply of energy.
The need for supply of external energy must be as a result of the high activation energy required for the reaction to go to completion. If a chemical reaction has a high activation energy, it will require an external supply of energy in order for such reaction to occur.