1- X g of hot water at 80 C is mixed with Y g cold water at 20 C in a perfect ca
ID: 873761 • Letter: 1
Question
1- X g of hot water at 80 C is mixed with Y g cold water at 20 C in a perfect calorimeter. If X > Y, which of the following is true for the final temperature of water? Assume heat exchange is only between water samples.
The final temperature will be exactly 50 C, which is the average of 80 and 20
The final temperature will be closer to 20 than to 80
The final temperature will be closer to 80 than to 20
2- At equal mass, will 100 C water or 100 C steam cause more serious burn? Why?
100 C steam because condensation of steam is exothermic
100 C steam because it occupies a bigger volume
100 C water because it is hotter
100 C water because evaporation of water is endothermic
3- What is the oxidation state of S in K2S2O3?
-2
+2
+4
0
+6
4- When acetic acid, CH3COOH, is dissolved in water, what is the major species (highest concentration) in the solution? Please do not consider water itself.
CH3CO+ and OH-
CH4 and CO2
H+ and CH3COO-
CH3COOH
5- When Steel wool was added to a blue colored CuCl2 solution, the color of solution gradually changed from blue to yellow. At the same time, there are some red solid covering the steel wool. What is causing the yellow color in the solution?
neutral Cu metal
neutral Fe metal
Fe2+ or Fe3+ ion
Cu2+ ion
6- When colorless NaOH solution is mixed with colorless HCl solution, what will happen?
Precipitation
Nothing obvious will happen, though there is a chemical reaction
Bubbling
Color change
7- What is the oxidizing agent of the following reaction?
NaBr + Cl2 --> NaCl + Br2
NaBr
Cl2
NaCl
Br2
8- Predict products of the following reaction:
Cl2 + KI -->
ICl + K
KCl + I2
ICl + K+
KCl +I-
9- Statue can be damaged by acid rain due to the reaction between CaCO3 in statue and the acid in acid rain. What is the driving force of this reaction? Select one best answer.
Precipitation
Formation of a weak electrolyte
Gas formation
Neutralization
10- What is the net ionic equation for the following chemical reaction?
2 NaOH(aq) + CO2(g) -->Na2CO3(aq) + H2O(l)
2 OH-(aq) + CO2(g) --> CO32-(aq) + H2O(l)
OH-(aq) + CO2(g) --> CO32-(aq) + H+(aq)
2 NaOH(aq) + CO2(g) -->Na2CO3(aq) + H2O(l)
2 Na+(aq) + 2 OH-(aq) + CO2(g) --> 2 Na+(aq) + CO32-(aq) + H2O(l)
The final temperature will be exactly 50 C, which is the average of 80 and 20
The final temperature will be closer to 20 than to 80
Explanation / Answer
1. The final T will be closer to 80
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