test 1 autumn 2012
#1 Assuming a magnesium atom is spherical, calculate its volume in nm3. The diameter
of a magnesium atom is 3.20 Å . The volume of a sphere is V = (4/3) r3.
1 Å = 1 x 10–10 m and 1 nm = 1 x 10–9 m and = 3.14
#2What is the maximum amount of carbon dioxide that can be produced by the combustion of 0.450g of C2H5OH?
#3What mass of FeCl3 would contain the same total number of ions as 16.8 g of Al2(SO4)3?
#4Heating MgSO4•7H2O at 150°C produces MgSO4•xH2O. If heating 24.4 g of pure MgSO4•7H2O at 150°C were to give 13.7 g of pure MgSO4•xH2O, calculate the value for x.
(a) 5(b) 4(c) 3(d) 2(e) 1
#5A sample of lead ore has a density of 8.80 g/mL. It is composed of two lead compounds: lead oxide, PbO (density 9.10 g/mL) and lead selenide, PbS (density 8.10 g/mL). What is the percent of the ore is lead oxide?
#6A mixture of 13.1 g Zn and 22.0 g I2 is reacted to completion in a closed, evacuated container. What are the contents of the container after this reaction?
Zn + I2 ZnI2
#7 If a reaction of 5.0 g of hydrogen with 5.0 g of carbon monoxide produced 4.5 g of methanol, what was the percent yield?
2H2 + CO CH3OH
(a) 11%(b) 79%(c) 96%(d) 24%(e) 63%
#8 In the sequential reactions shown below, the first reaction has an 80% yield and the second reaction has a 60% yield.
A + B C + D
C + E F
What is the yield of F?
1| 1.71 x 10-2 nm3|
2| 0.860 g carbon dioxide|
3| 9.99 g iron III chloride|
4| x = 1|
5| 70% lead II oxide|
6| 7.42 g Zn and 27.64 g zinc iodide|
7| 79 % yield |
8| 48% yield|