Question 17

Question

Match the solution to its description using the following diagram:

Column A
1.
20g of NaCl at 50°C:
20g of NaCl at 50°C
2.
45g KCl at 60°C:
45g KCl at 60°C
3.
70g of CaCl2 at 10°C:
70g of CaCl2 at 10°C
Column B
a.unsaturated
b.saturated
c.supersaturated
Question 18
The table shows the acceleration due to gravity on four different planets.
Mercury 3.59
Venus 8.87
Earth 9.81
Mars 3.77
What planet is a person standing on if the person has a mass of 35.0 kg and weighs 343 N?

a
Venus
b
Mars
c
Mercury
d
Earth

Question 19
Atoms and molecules are constantly in motion. The more kinetic energy atoms or molecules have, the faster they move about. In which state of matter do the atoms and molecules have the least kinetic energy?

a
not enough information to determine
b
liquid
c
solid
d
gas

Question 20
A reaction that produces heat is an endothermic reaction.

True
False
Question 21
What happens to the volume of a gas when the temperature is increased?

a
The volume stays the same
b
The volume is decreased
c
The volume is increased
Question 22
A box is initially at rest on a surface. It then experiences two forces, as shown in the picture.
The force on the left is 20N
the force on the right is 18N
Which best describes what will happen to the box?

a
It will move to the right.
b
It will move to the left.
c
It will remain at rest.
Question 23
What is the difference between speed and velocity?

a
Velocity has direction.
b
Velocity has time.
c
Velocity has distance.

d
Velocity has weight.

Question 24
Americium-241 is a radioactive substance used in smoke detectors. The half life of americium is 432 years. If a smoke detector initially contains 1 gram of Americium 241, how much will remain in 1,296 years?

a
1.0 g
b
0.5 g
c
0.125 g
d
0.25 g
Question 25
The table shows the times it took different animals to cover various distances.

MOTION OF ANIMALS
Animals Distance (km) Time (h)
Gray fox 73 1.05
Gazelle 68 0.85
Rabbit 70 1.25
Cheetah 85 0.75
Giraffe 60 1.15
Antelope 93 0.95


Which animal's speed is the greatest?

a
gray fox
b
cheetah
c
gazelle
d
rabbit
Question 26
Use the pictures below to answer these questions:

How does Magnesium become an ion? What is the charge of the Magnesium ion?



a
The magnesium atom gained two electrons. The ion has a positive two charge.
b
The magnesium atom lost two electrons. The ion has a positive two charge.
c
The magnesium atom lost two electrons. The ion has a negative two charge.
d
The magnesium atom gained two electrons. The ion has a negative two charge.
Question 27
A radioisotope has a half-life of 7.5 hours. How many half lives have occured after 67.5 hours?

a
7 half-lives
b
8 half-lives
c
9 half-lives
d
10 half-lives
Question 28
The chemical equation for the reaction between magnesium (Mg) and hydrochloric acid (HCl) is shown.

Mg + 2HCl → MgCl2 + H2

Fiona weighs the magnesium and hydrochloric acid before the reaction and finds a total mass of 55 grams. After the reaction, she measures the mass of the products, magnesium chloride (MgCl2) and hydrogen (H2), and finds a total mass of 55 grams again. Does Fiona's data support the law of conservation of matter, and why?

a
Yes, because the mass of the reactants is the same as the mass of the products in her data.
b
No, because the mass of the reactants is the same as the mass of the products in her data.
c
No, because the mass of the reactants is lower than the mass of the products in her data.
d
Yes, because the mass of the reactants is lower than the mass of the products in her data.

Answer 1

Here are the answers for each of your questions:

Question 17

1. 20g of NaCl at 50°C: b. saturated
2. 45g KCl at 60°C: c. supersaturated
3. 70g of CaCl2 at 10°C: a. unsaturated

Question 18
A person weighing 343 N has a mass of 35.0 kg.
Using \( \text{Weight} = \text{mass} \times \text{gravity} \),
\[ 343 , \text{N} = 35.0 , \text{kg} \times g \implies g = \frac{343}{35.0} \approx 9.8 , \text{m/s}^2 \]
This matches Earth.
Answer: d. Earth

Question 19
The state of matter with the least kinetic energy:
Answer: c. solid

Question 20
A reaction that produces heat is an exothermic reaction, not endothermic.
Answer: False

Question 21
What happens to the volume of a gas when the temperature is increased?
Answer: c. The volume is increased

Question 22
The net force on the box is \(20 , \text{N} - 18 , \text{N} = 2 , \text{N}\) to the left, so it will move to the left.
Answer: b. It will move to the left.

Question 23
What is the difference between speed and velocity?
Answer: a. Velocity has direction.

Question 24
Half-lives of 432 years for Americium-241:
\[ \text{In 1,296 years} = \frac{1,296}{432} = 3 \text{ half-lives} \] Starting with 1g:
1g → 0.5g → 0.25g → 0.125g
Answer: c. 0.125 g

Question 25
Calculate the speed for each animal:

• Gray fox: \( \frac{73}{1.05} \approx 69.52 , \text{km/h} \)
• Gazelle: \( \frac{68}{0.85} \approx 80.00 , \text{km/h} \)
• Rabbit: \( \frac{70}{1.25} \approx 56.00 , \text{km/h} \)
• Cheetah: \( \frac{85}{0.75} \approx 113.33 , \text{km/h} \)
• Giraffe: \( \frac{60}{1.15} \approx 52.17 , \text{km/h} \)
• Antelope: \( \frac{93}{0.95} \approx 97.89 , \text{km/h} \)

Greatest speed is by the Cheetah.
Answer: b. cheetah

Question 26
Magnesium becomes an ion by losing electrons:
Answer: b. The magnesium atom lost two electrons. The ion has a positive two charge.

Question 27
A half-life of 7.5 hours in 67.5 hours:
\[ \frac{67.5}{7.5} = 9 \text{ half-lives} \]
Answer: c. 9 half-lives

Question 28
Fiona's data shows the mass is conserved:
Answer: a. Yes, because the mass of the reactants is the same as the mass of the products in her data.

Feel free to ask if you need further assistance!