1.
Calculate the density of an object with a mass of 5 g and a volume of 12 mL. Would it sink or float in water? (The density of water is 1 g/mL).
IN THE SPACE PROVIDED, SHOW HOW YOU CALCULATED YOUR ANSWER & WHETHER THE OBJECT WILL SINK OR FLOAT IN WATER.
2.
While burning coal and charcoal, you notice that coal releases more heat than charcoal. That means that the chemical potential energy is ________________ in charcoal than in coal.
Correct Answer
A. Lower
Explanation
The given answer, "lower," is correct because the statement indicates that coal releases more heat than charcoal when burned. This suggests that coal has a higher chemical potential energy compared to charcoal. Therefore, the chemical potential energy is lower in charcoal than in coal.
3.
When you touch an ice cube, heat is transferred from________ to________
Correct Answer
your finger, your hand
the ice cube, the ice
Explanation
When you touch an ice cube, heat is transferred from your finger to the ice cube. This is because heat always flows from a higher temperature object (your finger) to a lower temperature object (the ice cube) until both objects reach thermal equilibrium. Additionally, heat is also transferred from your hand to the ice cube since your hand is in contact with your finger.
4.
You have four water samples at different temperatures. In which sample are the molecules vibrating at the fastest speed?
Correct Answer
B. Water at 99 oC
Explanation
The molecules in a substance vibrate faster as the temperature increases. Since 99°C is the highest temperature among the given options, the water at 99°C would have the molecules vibrating at the fastest speed.
5.
In a chemistry experiment, the total energy contained in a system is 45 J. After the system undergoes a chemical reaction, the total energy in the system is 39 J. Which of the following statements is true?
Correct Answer
B. The surroundings gained 6 J
Explanation
According to the law of conservation of energy, energy cannot be created or destroyed, only transferred or transformed. In this case, the total energy in the system decreased from 45 J to 39 J, indicating that 6 J of energy was transferred out of the system. Since the energy cannot simply disappear, it must have been transferred to the surroundings, resulting in the surroundings gaining 6 J of energy.
6.
You leave each of the following items outside on a hot, sunny day. Once the sun goes down, which item will cool off the fastest?
Correct Answer
B. Gold bracelet
Explanation
Gold is a good conductor of heat, meaning it can absorb and transfer heat quickly. On a hot, sunny day, the gold bracelet will absorb a significant amount of heat from the sun. However, once the sun goes down, gold's high thermal conductivity will allow it to release the absorbed heat quickly, resulting in faster cooling compared to the other items.
7.
Which is an example of kinetic energy?
Correct Answer
A. An arrow in flight
Explanation
An arrow in flight is an example of kinetic energy because it possesses both mass and velocity. As the arrow moves through the air, it has the ability to do work and transfer energy due to its motion. The arrow's kinetic energy is directly related to its speed and mass, with faster and heavier arrows possessing more kinetic energy.
8.
According to the law of conservation of mass, mass is __________________. Select ALL that apply.
Correct Answer(s)
A. Conserved during chemical reactions
B. Always conserved over time
C. Conserved during pHysical transformations
Explanation
According to the law of conservation of mass, mass is conserved during chemical reactions, always conserved over time, and conserved during physical transformations. This means that the total mass of a system remains constant, regardless of any changes in the form or state of the substances involved. Mass cannot be created or destroyed, only transformed or rearranged.