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d d d d d d d d
Question 1 d
Complete the two problems below: d d d d
1. Convert 0.0000726 to exponential form and explain your
d d d d d d d
answer.
d
2. Convert 5.82 x 103 to ordinary form and explain your answer.
d d d
d
d d d d d d
Answer:
1. Convert 0.0000726 = smaller than 1 = negative exponent, move
d d d d d d d d d
d decimal 5 places = 7.26 x 10 d d d d d d
-5
2. Convert 5.82 x 103 = positive exponent = larger than 1, move
d d d
d
d d d d d d d
d decimal 3 places = 5820 d d d d
Question 2 d
Do the conversions shown below, showing all work:
d d d d d d d
1. 358oK = ? oC d d d
2. 53oC = ? oF d d d
3. 158oF = ? oK d d d
Answer:
1. 358oK - 273 = 85 oC d d d d d K → oC (make smaller)
o
d d d d
-273
2. 53oC x 1.8 + 32 = 127.4 oF d d d d d d d
o
C → oF (make larger)
d d d d
x d
1.8 + 32 d d
3. 158oF - 32 ÷ 1.8 = 70 + 273 = 343 oKd d d d d d d d d d d
o
F → oC → oK
d d d d
Question 3 d
Show the calculation of the number of moles in the given amount of
d d d d d d d d d d d d
the following substances. Report your answerto 3 significant
d d d d d d d d
figures.
d
1. 12.0 grams of Ca3(PO4)2 d d d
, 2. 15.0 grams of C9H8NO4Cl d d d
Answer:
1. Moles = grams / molecular weight = 12..18 = 0.0387
d d d d d d d d d d d
mole d
2. Moles = grams / molecular weight = 15..61 = 0.0653
d d d d d d d d d d d
mole
d
Question 4 d
Show the calculation of the percent of each element present in the
d d d d d d d d d d d
following compounds. Report your answer to 2 places after the
d d d d d d d d d d
decimal.
d
1. Al2(SO4)3
2. C7H5NOBr
Answer:
1. %Al = 2 x 26.98/342.17 x 100 = 15.77% d d d d d d d d %S = 3 xd d d
32.07/342.17 d
x 100 = 28.12%
d d d
%O = 12 x 16/342.17 = 56.11%
d d d d d d
2.
%C = 7 x 12.01/ 199.02 x 100 = 42.24% %H = 5 x 1.008/ 199.02 x
d d d d d d d d d d d d d d d
100
d
= 2.53% d
%N = 1 x 14.01/199.02 = 7.04%
d d d d d d %O = 1 x 16.00/199.02 x
d d d d d
100
d
= 8.04% d
%Br = 79.90/199.02 x 100 = 40.15%
d d d d d d
Question 5 d
Show the calculation of the heat of reaction (ΔHrxn) for the
d d d d d d d d d d
d reaction: CH4 (g) d d + 2 O2 (g) →
d d CO2 (g) d +
2 H2O (l)
d d
d d d d d d d d
Question 1 d
Complete the two problems below: d d d d
1. Convert 0.0000726 to exponential form and explain your
d d d d d d d
answer.
d
2. Convert 5.82 x 103 to ordinary form and explain your answer.
d d d
d
d d d d d d
Answer:
1. Convert 0.0000726 = smaller than 1 = negative exponent, move
d d d d d d d d d
d decimal 5 places = 7.26 x 10 d d d d d d
-5
2. Convert 5.82 x 103 = positive exponent = larger than 1, move
d d d
d
d d d d d d d
d decimal 3 places = 5820 d d d d
Question 2 d
Do the conversions shown below, showing all work:
d d d d d d d
1. 358oK = ? oC d d d
2. 53oC = ? oF d d d
3. 158oF = ? oK d d d
Answer:
1. 358oK - 273 = 85 oC d d d d d K → oC (make smaller)
o
d d d d
-273
2. 53oC x 1.8 + 32 = 127.4 oF d d d d d d d
o
C → oF (make larger)
d d d d
x d
1.8 + 32 d d
3. 158oF - 32 ÷ 1.8 = 70 + 273 = 343 oKd d d d d d d d d d d
o
F → oC → oK
d d d d
Question 3 d
Show the calculation of the number of moles in the given amount of
d d d d d d d d d d d d
the following substances. Report your answerto 3 significant
d d d d d d d d
figures.
d
1. 12.0 grams of Ca3(PO4)2 d d d
, 2. 15.0 grams of C9H8NO4Cl d d d
Answer:
1. Moles = grams / molecular weight = 12..18 = 0.0387
d d d d d d d d d d d
mole d
2. Moles = grams / molecular weight = 15..61 = 0.0653
d d d d d d d d d d d
mole
d
Question 4 d
Show the calculation of the percent of each element present in the
d d d d d d d d d d d
following compounds. Report your answer to 2 places after the
d d d d d d d d d d
decimal.
d
1. Al2(SO4)3
2. C7H5NOBr
Answer:
1. %Al = 2 x 26.98/342.17 x 100 = 15.77% d d d d d d d d %S = 3 xd d d
32.07/342.17 d
x 100 = 28.12%
d d d
%O = 12 x 16/342.17 = 56.11%
d d d d d d
2.
%C = 7 x 12.01/ 199.02 x 100 = 42.24% %H = 5 x 1.008/ 199.02 x
d d d d d d d d d d d d d d d
100
d
= 2.53% d
%N = 1 x 14.01/199.02 = 7.04%
d d d d d d %O = 1 x 16.00/199.02 x
d d d d d
100
d
= 8.04% d
%Br = 79.90/199.02 x 100 = 40.15%
d d d d d d
Question 5 d
Show the calculation of the heat of reaction (ΔHrxn) for the
d d d d d d d d d d
d reaction: CH4 (g) d d + 2 O2 (g) →
d d CO2 (g) d +
2 H2O (l)
d d
