Agas collected from a reaction has a mass of 1.211 g and occupies a volume of 0.677 l. the temperature in the laboratory is 296 k, and the air pressure is 0.987 atm. calculate the molar mass of the gas.

a) 23.7 g/mol
b) 44.0 g/mol
c) 58.5 g/mol
d) 82.3 g/mol

B) 44.0 g/mol

Explanation:

To solve this problem we use the law of ideal gases, according to which ,

PV = nRT

where P, V, n and T are the pressure, volume, moles and temperature of the gas in question while R is the constant gas (0.082057 atm L / mol K)

The molar mass (MM) of a substance is given by

MM = m / n

where m is the mass of the substance. So,

n = m / MM

Substituting in the ideal gas equation we have

PV = () RT  →  MM =

→ MM =

→ MM = 44.0 g/mol

B) 44.0 g/mol

Explanation:

To solve this problem we use the law of ideal gases, according to which ,

PV = nRT

where P, V, n and T are the pressure, volume, moles and temperature of the gas in question while R is the constant gas (0.082057 atm L / mol K)

The molar mass (MM) of a substance is given by

MM = m / n

where m is the mass of the substance. So,

n = m / MM

Substituting in the ideal gas equation we have

PV = () RT  →  MM =

→ MM =

→ MM = 44.0 g/mol

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.