Math of chem

Question 1

Treat the numbers as subscripts. What is the gram formula mass of H2O and Al2O3?

Answer 1

H2O 18.0 grams Al2O3 82.0 g

Question 2

Treat the numbers as subscripts. What is the gram formula mass of Ba(NO3)2?

Answer 2

261.3 grams

Question 3

Treat the numbers as subscripts. What is the percent composition of Al in Al2O3 (with the setup)?

Answer 3

Al2/Al2O3 x100= 65.9%

Question 4

Treat the numbers as subscripts. How much aluminium could be extracted from 200.grams of bauxite (Al2O3), which is 65.9% Al?

Answer 4

131.7 grams

Question 5

A 5.0g of a BaCl2 hydrate was heated to a constant mass of 4.3g. What is the percent water in the hydrate?

Answer 5

14.0%

Question 6

Treat the numbers as subscripts. If the empirical formula is CH2 and the molecular mass is 42, what is the molecular formula?

Answer 6

C3H6

Question 7

Treat the numbers as subscripts. How many grams are in 2.0 moles of H2O?

Answer 7

36.0g

Question 8

Treat the numbers as subscripts. How many moles are in 9.0 grams of H2O?

Answer 8

.5 moles

Question 9

How can you identify a synthesis reaction?

Answer 9

There is only 1 type of product.

Question 10

What type of reaction has only 1 type of reactant?

Answer 10

decomposition

Question 11

How can you identify a single replacement reaction?

Answer 11

element + compound

Question 12

What reaction has a compound + compound making 2 new compounds?

Answer 12

double replacement

Question 13

How can you tell a reaction is balanced? If it isn’t balanced, what do you change to balance it?

Answer 13

A reaction is balanced by having the same number of atoms on each side of the equation. Balancing is done by changing coefficients.