Experiment 7: Gas Laws 2- The ideal gas equation

Question 1

The equivalent weight of a substance is…?

Answer 1

The weight of the substance that will produce one mole of hydrogen atoms

Question 2

Magnesium and HCL reaction equation (reaction in this experiment)?

Answer 2

Mg(s) + 2HCL(aq)–> MgCl2 + H2(g). 1 mole H needs 1/2 mole Mg

Question 3

Final pressure of dry gas equals.

Answer 3

Pg=Pb-Pwv-Pw
b=barometric
wv=water vapor
w=water

Question 4

Procedure:

Answer 4

1) Weigh Mg ribbon, wipe with steel wool to remove oxidation (MgO)
2) React

Question 5

Pw=

Answer 5

delta H/13.6

Question 6

mmH20 –>mmHg=torr

Answer 6

1/13.6

Question 7

How do you calculate the equivalent of H2

Answer 7

Volume H2 at STP/11.2

Question 8

The number of equivalents of Mg =

Answer 8

the number of equivalents of H2

Question 9

Equivalent weight of Mg=

Answer 9

grams Mg/# of equivalents

Question 10

Oxidation state of Mg=

Answer 10

Atomic weight of Mg/equivalent weight of Mg

Question 11

Classify the reaction in this experiment (gas laws 2)

Answer 11

Simple displacement; gas evolution

Question 12

Why can you add water to acid in this experiment?

Answer 12

The HCL is concentrated enough to have a large enough density differential to create layers. Also pour gently

Question 13

Why wipe with steel wool?

Answer 13

Remove MgO oxidation

Question 14

Why do we need the “dry” gas pressure?

Answer 14

That’s what you need to use PV=nRT

Question 15

Equivalent weight of Hydrogen?

Answer 15

1.008

It assumes valence 1

Question 16

How many electrons are involved in 1 equivalent of oxidation-reduction?

Answer 16

2.

Mg^2+

Question 17

True/false? Can you have non-integral values for the oxidation state?

Answer 17

True, you can

Question 18

equivalent weight=

Answer 18

molar mass/oxidation state (2,3 etc)