12 Chemistry 2012 class
Mole calculations and
gravimetric analysis: test #1
Date: Tuesday 7 February 2012
Q1. Which of the following is an empirical
formula?
A.
B.
C.
D.
H2SO4
C2H6
CH3COOH
P4O10
0%
A.
0%
B.
0%
C.
0%
D.
Q2. In an analysis of a gas, the mass of 5.00L at STP was
found to be 13.1g. Which of the following is the gas
most likely to be?
A.
B.
C.
D.
Cl2
H2
CO2
SO2
0%
A.
0%
B.
0%
C.
0%
D.
Q3. Consider the following equation:
2Al(s) + Cr2O3(s) → Al2O3(s) + 2Cr(s)
What is the theoretical yield of chromium that can be
produced by the reaction of 40.0g of Cr2O3 with 8.00g
of aluminium?
A.
B.
C.
D.
7.70g
15.4g
27.3g
30.8g
0%
A.
0%
B.
0%
C.
0%
D.
Q4. The largest number of hydrogen atoms will
be present in:
A. 0.40 mol of NH4Cl
B. 200mL of 5M HNO3
C. 18g of glucose (C6H12O6)
where M = 180 g mol-1
D. 0.60 mol of hydrogen
gas
0%
1
0%
2
0%
3
0%
4
Q5. A hydrocarbon has an empirical formula of
CH2 and a molecular mass of 56. The molecular
formula of the molecule is:
A.
B.
C.
D.
CH2
C2H4
C3H6
C4H8
0%
A.
0%
B.
0%
C.
0%
D.
Q6. A bottle of bleach contains 43g of sodium
hypochlorite (NaOCl) per litre of solution. This
concentration is equivalent to:
A.
B.
C.
D.
43% m/m
43 ppm
0.058 mol per litre
0.58 M
0%
A.
0%
B.
0%
C.
0%
D.
Q7. In a gravimetric analysis of fertiliser a student precipitated
barium sulfate to analyse for sulfate ions , but her calculated
result was higher than expected. This error could be due to:
A. some of the precipitate
went through the filter
paper.
B. the student did not dry the
precipitate sufficiently.
C. some of the precipitate
remained in the beaker.
D. the student did not use
excess barium ions.
0%
A.
0%
B.
0%
C.
0%
D.
Q8. When performing a gravimetric analysis, a student
forgot to wash the precipitate with deionised water.
The final result will be:
A. Unchanged.
B. Smaller than it should
have been.
C. Larger than it should
have been.
D. Any effect will depend
on the chemical formula of
the precipitate formed.
0%
1
0%
2
0%
3
0%
4
Q9. A gravimetric analysis was used to determine the amount of
salt (sodium chloride) in a packet of noodles. An appropriate
precipitating agent to use would be:
A.
B.
C.
D.
Hydrochloric acid.
Silver nitrate.
Magnesium hydroxide.
Potassium sulfate.
0%
1
0%
2
0%
3
0%
4
Q10. Which of the following experimental procedure
errors will NOT have any effect on the calculated mass
of the element under investigation?
A. The precipitate was still wet
when it was weighed.
B. More than one compound
was present that reacted
with the precipitating agent.
C. The student used gravity to
remove the filtrate from the
precipitate rather than
vacuum filtration
D. The filter paper has a small
hole in it.
0%
A.
0%
B.
0%
C.
0%
D.