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3 years ago

Which one of these samples contains the smallest number of molecule?

Chemistry

1 answer:

erma4kov [3.2K]3 years ago

8 0

Answer:

E) 1.0L of He at STP

Explanation:

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A piston containing 0.120moles of methane gas, CH4, has a volume of 2.12liters. If methane is added until the volume is increase

earnstyle [38]

Answer:

2.83 g

Explanation:

At constant temperature and pressure, Using Avogadro's law

$\frac {V_1}{n_1}=\frac {V_2}{n_2}$

Given ,

V₁ = 2.12 L

V₂ = 3.12 L

n₁ = 0.120 moles

n₂ = ?

Using above equation as:

$\frac{2.12}{0.120}=\frac{3.12}{n_2}$

$2.12n_2=0.12\cdot \:3.12$

$2.12n_2=0.3744$

$n_2=\frac{0.3744}{2.12}$

$n_2=0.17660$

n₂ = 0.17660 moles

Molar mass of methane gas = 16.05 g/mol

So, Mass = Moles*Molar mass = 0.17660 * 16.05 g = 2.83 g

<u>2.83 g are in the piston.</u>

8 0

3 years ago

What is the value for AG at 100 Kif AH = 27 kJ/mol and AS = 0.09 kJ/(mol-K)?

Elina [12.6K]

Answer:

ΔG = 18KJ/mol

Explanation:

Given data:

ΔS = 0.09 Kj/mol.K

ΔH = 27 KJ/mol

Temperature = 100 K

ΔG = ?

Solution:

Formula:

ΔG = ΔH - TΔS

ΔH = enthalpy

ΔS = entropy

by putting values,

ΔG = 27 KJ/mol - 100K(0.09 Kj/mol.K)

ΔG = 27 KJ/mol - 9 KJ/mol

ΔG = 18KJ/mol

7 0

2 years ago

The normal freezing point of a certain liquid

stepladder [879]

Answer : The molal freezing point depression constant of X is $4.12^oC/m$

Explanation : Given,

Mass of urea (solute) = 5.90 g

Mass of X liquid (solvent) = 450.0 g

Molar mass of urea = 60 g/mole

Formula used :

$\Delta T_f=i\times K_f\times m\\\\T^o-T_s=i\times K_f\times\frac{\text{Mass of urea}\times 1000}{\text{Molar mass of urea}\times \text{Mass of X liquid}}$

where,

$\Delta T_f$ = change in freezing point

$\Delta T_s$ = freezing point of solution = $-0.5^oC$

$\Delta T^o$ = freezing point of liquid X= $0.4^oC$

i = Van't Hoff factor = 1 (for non-electrolyte)

$K_f$ = molal freezing point depression constant of X = ?

m = molality

Now put all the given values in this formula, we get

$[0.4-(-0.5)]^oC=1\times k_f\times \frac{5.90g\times 1000}{60g/mol\times 450.0g}$

$k_f=4.12^oC/m$

Therefore, the molal freezing point depression constant of X is $4.12^oC/m$

4 0

3 years ago

49.Which of the following statements regarding chemical equilibrium is true?

crimeas [40]

A asystem at equilibrium stops

8 0

3 years ago

Does a negative exponent mean that the number is less than 1 yes or no

Masja [62]

Answer:

When a number is written in scientific notation, the exponent tells you if the term is a large or a small number. A positive exponent indicates a large number and a negative exponent indicates a small number that is between 0 and 1.

3 0

2 years ago