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Find ΔΕ
a) When 175 kJ of work is done on a system that evolves 50 J of heat to the surroundings
b) When a gas absorbs 28 kJ and has 13 kJ of work done on it
B. Consider the following reaction in a container with a movable piston:
A(I) + B(I) = C(g)
The ΔE for this reaction is 760 J. As the piston moves up, the system absorbs 839J of heat from its surroundings.
1. Is work done on the system?
2. How much work?
Write the thermochemical equation for the following reactions that occur at constant pressure:
a.Decomposition of mercuric oxide, HgO, to mercury and oxygen gas, requires 87.1 kJ of heat
b.Combustion of hexane, C6H12, to carbon dioxide gas and water releases 3923.9 kJ of heat
Find the formula charge of each atom in the given compounds/polyatomic
ion.
1. HBr
2. N 2 O
3. SO 4 2-
A ballon has a volume of 75.0-L when it is released at a pressure of 130kpa. What will the balloons volume be when it reaches an altitude with a pressure of 100kpa
Explain why a starch solution turns purple when iodine is added to it, but then turns
colourless again within 30 min after saliva is added to it.
Draw the following: Show all atoms.
A. Fischer projections of the linear structures of both the D and L enantiomers of glucose. On
these structures indicate how the D-enantiomer is distinguished from the L-enantiomer.
B. Haworth projections of both anomers that can form when D-glucose cyclizes in water.
Indicate the anomeric carbon. Name these anomers and explain how they are named.
C. Haworth projection of β-D-fructose. Explain why this sugar is referred to as a ketohexose
sugar and a furanose sugar.
In the periodic table the size of atoms decrease from left to right because
April is moving into a new apartment. She is moving a box of books that has a mass of 30 kg.
a. What is the weight of the box? (2 points)
b. What is the normal force acting on the box when it sits on the floor? Explain how you found the answer. (2 points)
c. If she pushes on the box with a force of 100 N and there is no friction, what is the acceleration of the box? (2 points)
d. If the coefficient of static friction between the box and the floor is 0.3, what is the maximum force of static friction acting on the box? (2 points)
e. How hard must she push on the box to get it to slide? (2 points)
f. If she pushes on the box with a force of 100 N, and the coefficient of kinetic friction is 0.25, what is the net force on the box in the x-direction? (2 points)
g. Based on your answer to part (f), what is the acceleration of the box? (2 points)
A toy dart gun uses a spring with a spring constant of 35 N/m. To use the dart gun, you compress the spring by pushing in a dart of mass 0.002 kg.
a. If you compress the spring by 0.02 m, what force is the spring exerting on the dart? (2 points)
b. With the spring compressed 0.02 m, how much elastic potential energy is stored in the spring? (3 points)
c. If you release the spring, it pushes the dart forward. What is the kinetic energy of the dart when it reaches the natural length of the spring? Explain how you found the answer. (2 points)
