Chemical Formulas & Counting Atoms
Which of the following is an example of an element?
A. Water (H2O)
B. Carbon Dioxide (CO2)
C. Oxygen (O2)
D. Table Salt (NaCl)
C. Oxygen (O2)
Which statement describes an action that most likely resulted in a chemical reaction?
A. A pan of water was heated on a stove, and steam formed.
B. A liquid was mixed with another liquid, and a precipitate formed.
C. A liquid was sprayed into the air, and a sweet odor was smelled.
D. A child blew through a wand filled with soap, and bubbles were produced.
B. A liquid was mixed with another liquid, and a precipitate formed.
Which of the following best describes temperature?
A. The total amount of thermal energy in an object.
B. The average kinetic energy of the particles in a substance.
C. The total mass of moving molecules.
D. THe speed of heat transfer between two objects.
B. The average kinetic energy of the particles in a substance.
Newton's First Law of Motion states that an object in uniform motion will remain in uniform motion, and an object at rest will remain at rest unless acted upon by an ___________ force.
A runner covers a distance of 100 meters in 20 seconds. What is the runner's average speed in meters per second (m/s)?
5 m/s
Two chemical formulas are shown below:
Barium Sulfate, BaSO4
Barium Hydroxide, Ba(OH)2
Which substance, Barium Sulfate or Barium Hydroxide, has more oxygen?
Barium Sulfate, BaSO4
Which of these observations is an indication that a chemical reaction has occurred?
A. Steam forms above boiling water
B. A solid forms when a clear solution is frozen.
C. A solid forms when two clear solutions are mixed.
D. Sugar crystals form on the sides of boiling pot of sugar water.
C. A solid forms when two clear solutions are mixed.
When particles in a substance move faster, their ___________ energy increases, which causes the substance's ___________ to rise.
kinetic, temperature
A ball rolls along a flat surface and slowly comes to a stop. Which statement best describes the reason for the ball's change in motion?
A. The force that keeps the ball rolling slowly decreases.
B. The force of gravity gets stronger as the ball slows down.
C. The ball's velocity decreases because of the force of friction
D. The ball's inertia is greater than the force applied to the ball.
C. The ball's velocity decreases because of the force of friction.
A dolphin swims a distance of 180 meters in 30 seconds. What is the dolphin's average speed in meters per second (m/s)?
6 m/s
The mineral albite is composed of four elements and has a chemical formula NaAlSi3O8. Which of the following elements does albite contain?
A. Astatine
B. Sulfur
C. Nitrogen
D. Aluminum
D. Aluminum
Which statement best describes evidence that a chemical reaction occurs as a cake bakes?
A. The water in the cake batter evaporates.
B. The cake rises as gas bubbles form in the baking cake.
C. The cake takes the shape of the container in which it is baked.
D. The water in the cake batter is used to keep the cake moist as it bakes.
B. The cake rises as the gas bubbles form in the baking cake.
In which direction does the thermal energy naturally transfer between two touching objects?
A. From the denser object to the less dense object.
B. From the smaller object to the larger object
C. From the warmer object to the cooler object.
D. From the cooler object to the warmer object.
C. From the warmer object to the cooler object.
A large rock is motionless on a flat sidewalk. Which statement best explains why the rock remains motionless?
A. There are no forces acting on the rock.
B. The only force acting on the rock is directed toward the sidewalk.
C. The forces acting on the rock are all balanced.
D. The sidewalk exerts an unbalanced force on the rock.
C. The forces acting on the rock are all balanced.
Two students record the distance they each traveled in 60 seconds.
Student 1 traveled 40 meters in 60 seconds.
Student 2 traveled 20 meters in 60 seconds.
If the students continue at the same speed, which statement describes the total distance traveled after 90 seconds?
A. Student 1 traveled 40 m, and student 2 traveled 20 m.
B. Student 1 traveled 50 m, and student 2 traveled 30 m.
C. Student 1 traveled 60 m, and student 2 traveled 30 m.
D. Student 1 traveled 70 m, and student 2 traveled 25 m.
C. Student 1 traveled 60 m, and student 2 traveled 30 m.
Ammonium phosphate, (NH4)3PO4, is a common ingredient in fertilizers How many atoms of nitrogen are in the formula for ammonium phosphate?
3
Researchers are investigating processes that happen during digestion. Which answer choice describes only physical change during digestion?
A. Hydrochloric acid in the stomach breaks down proteins
B. Chewing in the mouth breaks food into small pieces.
C. Enzymes in saliva start the digestion of starches before food is swallowed.
D. Bacteria in the intestines convert dietary fiber into fats.
B. Chewing in the mouth breaks down food into smaller pieces.
What happens when two objects in contact reach thermal equilibrium?
A. Heat stops transferring because both temperatures are equal.
B. One object loses all of its thermal energy.
C. Particle motion stops completely in both objects.
D. The colder object becomes hotter than the warm object.
A. Heat stops transferring because both temperatures are equal.
The tendency of an object to resist any change in it's state of motion is called __________ .
inertia.
A car traveled a distance of 100 kilometers in 1 hour. The car stopped for 1 hour and then traveled an additional 140 km in 2 hours. What was the average speed of the car in kilometers per hour over the course of the entire trip, including when the car was stopped?
A. 60 km/h
B. 80 km/h
C. 85 km/h
D. 120 km/h
A. 60 km/h
The chemical formula for acetic acid is CH3COOH. How many hydrogen atoms are in one molecule of acetic acid?
4
A teacher performs these steps for a class to demonstrate, and students record their observations.
1. Put a small candle in a candleholder
2. Light a match
3. Use the flame from the match to light the candle.
4. Let the candle burn for 5 minutes.
5. Blow out the flame.
6. Let the students examine the candle after it has cooled.
What is an example of a physical change that occurred during the demonstration AND what is an example of a chemical change that occurred during the demonstration?
Physical Change: The candle wax melting.
Chemical Change:
Let the candle burn for 5 minutes.
OR
Light a match
OR
Use the flame from the match to light the candle
Which scenario is a primary example of heat transfer by convection?
A. Feeling heat from a lightbulb without touching it.
B. Solar energy heating an asphalt driveway
C. A metal spoon getting hot in hot tea.
D. Warm water rising and cool water sinking in a pot.
D. Warm water rising and cool water sinking in a pot.
If you throw a baseball in deep space, far away from gravity or air friction, it will keep moving at a ________ _________ forever.
constant speed.
A horse trainer records the distance a horse travels during three different trials.
During Trial 1, the horse traveled 4.5 kilometers in 15 minutes.
During Trial 2, the horse traveled 9.0 kilometers in 30 minutes.
During Trial 3, the horse traveled 13.5 kilometers in 45 minutes.
What is the horse's average speed in kilometers per minute?
0.3 km/min