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Brilliant_brown [7]
3 years ago
13

A 3.42 gram sample of an unknown gas is found to occupy a volume of 1.90 L at a pressure of 547 mm Hg and a temperature of 33 °C

. The molecular weight of the unknown gas is ___ g/mol.
Chemistry
1 answer:
liq [111]3 years ago
3 0
Use the Ideal Gas Law to find the moles of gas first.

Be sure to convert T from Celsius to Kelvin by adding 273.

Also I prefer to deal with pressure in atm rather than mmHg, so divide the pressure by 760 to get it in atm.

PV = nRT —> n = PV/RT
P = 547 mmHg = 547/760 atm = 0.720 atm
V = 1.90 L
T = 33°C = 33 + 273 K = 306 K
R = 0.08206 L atm / mol K

n = (0.720 atm)(1.90 L) / (0.08206 L atm / mol K)(306 K) = 0.0545 mol of gas

Now divide grams by mol to get the molecular weight.

3.42 g / 0.0545 mol = 62.8 g/mol
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For the Bradford assay, the instructor will make a Bradford reagent dye by mixing 50 ml of 95% v/v ethanol with 100 mg of Coomas
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Answer:

4.25% is the final concentration of phosphoric acid.

Explanation:

Initial concentration of phosphoric acid = C_1=85\%=0.85

Initial volume of phosphoric acid = V_1=50 mL

Final concentration of phosphoric acid = C_2=?

Final volume of phosphoric acid = V_2=1 L=1000 mL

( 1L = 1000 mL)

C_1V_1=C_2V_2

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=\frac{0.85\times 50 mL}{1000 mL}=0.0425=4.25%

4.25% is the final concentration of phosphoric acid.

4 0
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The atomic mass of potassium is 39.1. What is the mass of 6.02 × 1023 atoms of potassium? . . A.. 39.1 mg. . . . . B.. 39.1 g. .
Sholpan [36]
Atomic mass of Potassium = Mass of 1 atom of Potassium = 39.1 amu
Then
Mass of 6.02 x 1023 atoms of potassium = 39.1 x 6.02 x 1023 amu
                                                                  = 
We already know that
1 mole = 6.02 x 1023 atoms
Also
Number of mole = mass in grams/ atomic mass
Then
Mass in gram = Number of mole x atomic mass
                       = (39.1 x 6.02 x 1023)/(6.02 x 1023)
                       = 39.1 g
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Brilliant_brown [7]

Answer:

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Explanation:

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2. concentration and pressure of reactants. pressure is for gases.

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CATALYST

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