8th grade science STAAR Review – Most Commonly Missed Concepts

In the chemical reaction shown above, the products are best classified as —

• two elements

• one element and one compound

• two compounds

• two compounds and one element

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

Which of these data tables correctly classifies the given substances?

• NaCl: compound, Si: element, H2O: compound

• NaCl: element, Si: element, H2O: element

• NaCl: element, Si: element, H2O: compound

• NaCl: compound, Si: compound, H2O: compound

Tags

NGSS.MS-PS1-1

The chemical equation shown below represents a reaction that produces fuel for certain cars. CO + H2O → CO2 + H2 Which substance represented in this equation is classified as an element?

• CO

• H2O

• CO2

• H2

Tags

NGSS.MS-PS1-1

A toy car rolls 8 meters in 2 seconds. What is the average speed of the toy car?

• 16 m/s

• 10 m/s

• 6 m/s

• 4 m/s

Which graph shows an object moving forward at a constant speed?

• Graph A

• Graph B

• Graph C

• Graph D

Tags

NGSS.MS-PS3-1

The graph below represents the motion of a car. During what time was the car moving the fastest?

• From 0 to 2 minutes

• From 2 to 4 minutes

• From 4 to 6 minutes

• From 6 to 8 minutes

Tags

NGSS.MS-PS3-1

The graph below shows distance over time. Which of these situations could be represented by this graph?

• A. A student walks 1.5 km to a friend's house in 40 minutes. The two students then walk another 1.5 km to school in 20 minutes.

• B. A student walks 1.5 km to a friend's house in 20 minutes. The two students then walk another 1.5 km to school in 40 minutes.

• C. A student walks 1.5 km to a friend's house in 30 minutes. The two students then walk another 1.5 km to school in 30 minutes.

• D. A student walks 1.5 km to a friend's house in 20 minutes. The two students then walk another 1.5 km to school in 60 minutes.

Tags

NGSS.MS-PS3-1

Based on its chemical formula, which of the following substances is an organic compound?

• Urea, CH₄N₂O

• Ammonium sulfide, (NH₄)₂S

• Silane, SiH₄

• Sodium chloride, NaCl

Scientists are always trying to create new medicines. Which of the following would be the best combination of materials to make an organic molecule?

• carbon, hydrogen, oxygen, phosphorus, nitrogen, sulfur

• chlorine, hydrogen, oxygen, potassium, neon, sulfur

• chlorine, helium, oxygen, phosphorus, neon, sodium

• carbon, helium, oxygen, phosphorus, nitrogen, sodium

Tags

NGSS.MS-PS1-1

The table below shows the elemental composition of three different types of organisms. The X in the table represents which of the following elements?

• Calcium (Ca)

• Iron (Fe)

• Nitrogen (N)

• Sodium (Na)

Tags

NGSS.MS-LS1-1