Reading/Balancing Chemical Equations
Amounts of Reactants and Products
Limiting and Excess Reagents
Fun Stuff
100

Mg (s) + S (g) --> MgS (s) can be read as

One mole of Magnesium reacts with 1 mole of Sulfur to form 1 mole of Magnesium Sulfide

2 atoms Magnesium react with one atom of Sulfur to form one molecule of Magnesium Sulfide

24.31g Mg react with 32g S to form 56.31g MgS

100

In the following equation, if 4 moles of Br are used up, how many moles of CaBr2 would you expect to be formed (assume Ca is in excess)

Ca (s) + 2Br (g) ---> CaBr2

2 moles CaBr2

100

What is the difference between a limiting and excess reagent?

Limiting reactants are completely used up in a reaction, excess reactants are the ones that will have some left over

100

What is Dr. Bange's son eating in the first slide of the Ch.3 slideshow

Spaghetti

200

The substances that are used up are called ___, while the substances being formed are called ____

Reactants; Products
200

In the following equation, if 46g of Ca are used up, how many moles of CaBr2 would you expect to be formed (assume Br is in excess)

Ca (s) + 2Br (g) ---> CaBr2

1.15 moles CaBr2

200

I bought a 8-cup bag of flour, 6 eggs, and 3 cups of milk. A cake calls for 6 cups of flour, 4 eggs, and 3 cups of milk. What is my limiting reagent?

Milk

300

When balancing chemical reactions, it is important to:

Be sure that no matter is created or destroyed, namely, that there is the same amount of each atom on both sides of the equation

300

Ca (s) + 2Br (g)--> CaBr2 (s). If 98.3g CaBr2 are formed, how many moles of Br were used up?

0.98 mol Br

300

2NH3 (g) + CO2 (g) --> (NH2)2CO (aq) + H2O (l).

In this process, 742.4g NH3 is reacted with 1,366.9g CO2.

Which is the limiting reactant?

NH3

300

What is Dr. Bange's all-time favorite chemistry joke (he's said it like 3 times now)

The hydrogen peroxide joke

400
Balance the following equation:


CH4 + Cl2 ---> CCl4 + HCl

CH4 + 4Cl2 ---> CCl4 + 4HCl

400

2Li (s) + 2H2O (l) --> 2LiOH (aq) + H2 (g). How many grams of water are needed to produce 12.45g H2?

225.25g H2O

400

2NH3 (g) + CO2 (g) --> (NH2)2CO (aq) + H2O (l).

In this process, 742.4g NH3 is reacted with 1,366.9g CO2.

How much (NH2)2CO is produced (in grams)?

1,309.31g (NH2)2CO

500

Balance the following equation:

C12H22 (s) + O2 (g) --> CO2 (g) + H2O (g)

2C12H22O11 (s) + 35 O2 (g) ----->

24CO2 (g) + 22H2O (g)

500

C4H8O4 (s) + 4O2 (g) --> 4CO2 (g) + 4H2O (g).

If 444g of C4H8O4 is used up, how much H2O was produced (in grams)?

266.7g H2O

500

2NH3 (g) + CO2 (g) --> (NH2)2CO (aq) + H2O (l).

In this process, 742.4g NH3 is reacted with 1,366.9g CO2.

How much excess reactant is left (in grams)?

407.48g CO2 
500

Today's in lecture, what did Dr. Bange say was the limiting lego for his son?

Steering wheels

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