Selasa, 11 Mei 2010

stokiometri

Changing Mass to Number of Particles

This page is designed to help students practice written problems, and is meant to be printed out. Hit the print command and show all work in the spaces provided. Round answers correctly and show proper units.

Change the following masses to number of particles by:
A) dividing by the molar mass to get the number of moles, and then
B) multiplying number of moles by Avogadro's number

1. How many molecules does 36.0 grams of water represent?


2. How many molecules does 11.0 grams of CO2 represent?
3. How many atoms does 3.0 grams of carbon represent?



* 4. How many formula units does 200.0 grams of calcium carbonate represent?


Changing Moles of a Gas at STP to Volume

page is designed to help students practice written problems, and is meant to be printed out. Hit the print command and show all work in the spaces provided. Round answers correctly and show proper units.

Change the following moles of gases at STP to volume with the formula:
Total Volume of a gas at STP = # of moles x molar volume of a gas (22.4 L)

1. What would be the volume of 0.25 moles of chlorine gas at STP?


2. What would be the volume of 6.25 moles of helium gas at STP?
3. How many dm3 would a 3.50 mole sample of neon occupy at STP?



4. What is the volume of 1.0 mole of argon gas at STP?


Changing Volume fo a Gas at STP to Number of Moles

page is designed to help students practice written problems, and is meant to be printed out. Hit the print command and show all work in the spaces provided. Round answers correctly and show proper units.

Change the following volume of gases at STP to moles with the formula:
# of moles = Total Volume of a gas at STP / molar volume of a gas (22.4 L)

1. How many moles does 44.8 L of Hydrogen gas at STP represent?


2. A sample of Oxygen gas occupies 6.2 L at STP. How many moles does that represent?
3. How many moles of gas would occupy 112 dm3 at STP?



4. How many moles of neon would occupy 450 cm3 at STP?


Mass-Mass Problems

Identify the following chemical equations by type.


1. How many grams of NaCl will be produced when 22.85 g of HCl are neutralized by an excess of NaOH according to the equation below?

HCl + NaOH ---> H2O + NaCl

2. How many grams of potassium nitrate are required to produce 5.00 g of potassium nitrite according to the equation below?

2KNO3(s) ---> 2KNO2(s) + O2(g)


3. How many grams of magnesium oxide are produced when 10.00 grams of magnesium burn in an excess of oxygen, as shown below?

2Mg + O2 ---> 2MgO


4. How many grams of aluminum would react completely with 17.50 grams of copper (II) chloride according to the following equation?

Al(s) + CuCl2(aq) ---> AlCl3(aq) + Cu(s)


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