Fort Chem On-line Quiz - Stoichiometry
1
In a chemical equation, what is balanced is
-- Choose an answer --
atoms
moles
molecules
atoms and molecules
moles and atoms
2
The oxidation number of chromium in Na2CrO4 is
-- Choose an answer --
-2
+2
+6
-6
+8
3
The oxidation number of sulfur in S2O3^2- is
-- Choose an answer --
+8
+6
+4
+3
+2
4
How many grams of carbon are needed to react completely with 75.2 g of silicon dioxide according to the following equation?
SiO2(s) + C(s) ===> SiC(s) + CO(g)
-- Choose an answer --
15.0 g
61.5 g
20.5 g
32.8 g
45.1 g
5
If 35.0 g of bromine and 20.0 g of ammonia are allowed to react according to the equation below, what is the maximum amount of nitrogen that can be produced?
Br2(l) + NH3(g) ===> NH4Br(s) + N2(g)
-- Choose an answer --
2.05 g
5.15 g
6.13 g
41.2 g
60.5 g
6
The following reaction occurs in the head of a match.
P4S3(s) + O2(g) ===> P4O10(s) + SO2(g)
How many grams of oxygen are needed to react with 0.450 grams of P4S3?
-- Choose an answer --
0.0654 g
0.126 g
0.523 g
3.60 g
1.83 g
7
How many grams of CO2 are produced by the complete combustion of 5.00 grams of C2H2?
C2H2(g) + O2(g) ===> CO2(g) + H2O(l)
-- Choose an answer --
8.45 g
20.0 g
33.8 g
12.6 g
16.9 g
8
How many moles of magnesium(if any) remain when 5.00 grams of magnesium is burned in 2.50 grams of pure oxygen according to the equation?
Mg(s) + O2(g) ===> MgO(s)
-- Choose an answer --
0.206 mol
0.0497 mol
0.0781 mol
0.156 mol
zero, it is totally consumed
9
When 10.0 grams of mercury (II) oxide was decomposed,. a student obtained 5.00 grams of mercury. What was the percent yield??
HgO(s) ===> Hg(l) + O2(g)
-- Choose an answer --
46.0%
50.0%
54.0%
33.3%
10.0%
10
When 5.0 grams of sodium carbonate was treated with excess hydrochloric acid, 1.50 grams of carbon dioxide was obtained. What was the percent yield?
Na2CO3(s) + HCl(aq) ===> NaCl(aq) + H2O(l) + CO2(g)
-- Choose an answer --
16.6%
23.1%
72.3%
30.0%
34.1%
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