Notes #3

Grams to grams stoichiometry

4- step bridge

MASS-MASS STOICHIOMETRY!!

Example: How many grams of silver chloride are produced when 17.0 grams of silver (I) nitrate react with excess sodium chloride?

Mass - Mass Relationships

Write a balanced equation for the reaction. (Remember to look up the oxidation numbers so the formulas are correct).

Start with mass given. Calculate the number of moles of the “given”

substance. Use the mole ratio to determine the moles of the “required” (unknown)

substance to moles of the “given” substance.(Use the balanced equation.) Convert moles “required” to grams(molar mass conversion factor) .

AgNO3 = 170g/mole(molar mass conversion factor)

Mass - Mass Relationships

AgNO3 + NaCl AgCl + NaNO3

Start w/grams given

17.0 g AgNO3

169.88g AgNO3

1 MoleAgNO3

1 mole of given

Grams ofgiven

Moles“required”

Moles given

1 mol AgCl

1 mol AgNO3

Grams of“required”

1 mole“required”

grams produced

=

143.32 gAgCl

1 mol AgCl

= 14.3 g AgCl

given required

Problems:

How much silver carbonate is produced when 14.3 g of silver chloride reacts with excess sodium carbonate?

What kind of reaction is this? Double displacement. Write the balanced equation. AgCl + Na2CO3 2 2Ag2CO3 + NaCl

2AgCl + Na2CO3 Ag2CO3 + 2NaCl

Given

14.3g AgCl

Grams per mole

Moles of silver carbonate

Moles ofsilver chloride

1 molAg2CO3

2 molAgCl

Grams per moleof required substance

277 gAg2CO3

1 molAg2CO3

= 13.9 gAg2CO3

143gAgCl

1 molAgCl

Practice problems

1. In a spacecraft, the carbon dioxide exhaled by astronauts can be removed by its reaction with lithium hydroxide according to the following equation:

CO2 (g) + 2LiOH Li2CO3(s) + H2O (l)

How many moles of lithium hydroxide are required to react with 20 moles of caron dioxide?