A sample of gas has a mass of 38.7 mg. Its volume is 228 mL at a temperature of 53 ∘C and a pressure of 885 torr. Find the molar mass of the gas.

Molar mass of the gas = 3.91 g/mol

Explanation:

Let's apply the Ideal Gases Law to solve this:

We convert the pressure from Torr to atm → 885 Torr . 1atm / 760 Torr = 1.16 atm

We convert T°C to T°K → 53°C + 273 = 326 K

We convert the volume from mL to L → 228 mL . 1L/1000mL = 0.228L

Now we can replace = 1.16 atm . 0228L = n . 0.082 .326K

(1.16 atm . 0.228L) / (0.082 / 326K) = n → 9.89×10⁻³ moles.

Let's convert the mass from mg to g → 38.7 mg . 1g / 1000 mg = 0.0387 g

Molar mass → g/mol → 0.0387 g / 9.89×10⁻³ mol = 3.91 g/mol

answer: the primary difference between a hypothesis and a theory is that b hypothesis is falsifiable, but a theory has been proven to be correct. theory is an explanation of something that is happening but hypothesis is a guess of something that can happen

explanation:

when 25.0 ml of 0.700 mol/l naoh was mixed in a calorimeter with 25.0 ml of 0.700 mol/l hcl, both initially at 20.0 °c, the temperature increased to 22.1 °c. the heat capacity of the calorimeter is 279 j/°c.

the equation for the reaction is:

naoh + hcl → nacl + h₂o

moles of hcl = 0.0250 l hcl ×

0.700

mol hcl

1 l hcl = 0.0175 mol hcl

volume of solution = (25.0 + 25.0) ml = 50.0 ml

mass of solution = 50.0 ml soln ×

1.00

ml soln

= 50.0 g soln

δt=t2-t1

= (22.1 – 20.0) °c = 2.1 °c

the heats involved are

heat from neutralization + heat to warm solution + heat to warm calorimeter = 0

q1+q2+q3=0

nδh+mcδt+cδt=0

0.0175 mol ×

δh

+ 50.0 g × 4.184 j·g⁻¹°c⁻¹ × 2.1 °c + 279 j°c⁻¹ × 2.1 °c = 0

0.0175 mol ×

δh

+ 439.32 j + 585.9 j = 0

0.0175 mol ×

δh

= -1025.22 j

δh=1025.22j0.0175 mol= -58 600 j/mol = -58.6 kj/mol