Consider the reaction of zn metal with hydrochloric acid: zn(s) + 2hcl(aq) → zncl2(aq) + h2(g) if 2.57 g of zn is reacted with 0.500 moles of hcl in a 3.00 l container what pressure does the generated h2 exert against the container walls at 35.8 ℃?

The pressure exerted by hydrogen gas is 0.33 atm

Explanation:

To calculate the number of moles, we use the equation:

Given mass of zinc = 2.57 g

Molar mass of zinc = 65.4 g/mol

Putting values in above equation, we get:

We are given:

Moles of HCl = 0.500 moles

For the given chemical equation:

By Stoichiometry of the reaction:

1 mole of zinc reacts with 2 moles of HCl

So, 0.039 moles of zinc will react with = of HCl

As, given amount of HCl is more than the required amount. So, it is considered as an excess reagent.

Thus, zinc metal is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

1 mole of zinc reacts with 1 mole of Hydrogen gas

So, 0.039 moles of zinc will react with = of hydrogen gas

To calculate the pressure of hydrogen gas, we use the equation given by ideal gas:

PV = nRT

where,

P = Pressure of hydrogen gas = ?

V = Volume = 3.00 L

n = number of moles of hydrogen gas = 0.039 moles

R = Gas constant =

T = Temperature =

Putting values in above equation, we get:

Hence, the pressure exerted by hydrogen gas is 0.33 atm

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.