Mr. Hays 8th Grade STAAR Practice Test

Which statement accurately describes the atoms of a specific element?

• An indium, In, atom contains 115 protons inside the nucleus and 49 neutrons outside the nucleus.

• A scandium, Sc, atom contains 45 electrons outside the nucleus and 21 neutrons inside the nucleus.

• An aluminum, Al, atom contains 27 electrons and 27 protons inside the nucleus.

• A zinc, Zn, atom contains 30 protons inside the nucleus and 30 electrons outside the nucleus.

Tags

NGSS.MS-PS1-1

Four students were asked to name the parts of an atom that determine the atom's identity and chemical properties. The student's responses are shown in the table. Which student's responses are correct?

• student 1

• student 2

• student 3

• student 4

Tags

NGSS.MS-PS1-1

Students were asked to identify the location of elements in the periodic table based on clues printed on game cards. Based on the data, which periodic table shows the correct location of the four elements?

• 
• 
• 
• 

Tags

NGSS.MS-PS1-1

Some students conducted a laboratory investigation to learn more about the physical properties of different elements. They observed four samples and recorded their observations in the table. Based on these observations, which sample is most likely a nonmetal?

• sample 1

• sample 2

• sample 3

• sample 4

A student is using colored beads to make a model of aluminum sulfate, Al₂(SO₄)_3. Aluminum atoms are represented by blue beads, sulfur atoms by yellow beads, and oxygen atoms by green beads. What combination of beads should the student use for the model?

• 6 blue, 3 yellow, and 7 green

• 2 blue, 1 yellow, and 4 green

• 2 blue, 3 yellow, and 12 green

• 6 blue, 12 yellow, and 12 green

Tags

NGSS.MS-PS1-1

Some students in a chemistry lab conducted an investigation in which they added four different solid substance to separate beakers of water. They stirred the mixtures for one minute and then recorded their observations in the table below. Which substance most likely caused a new substance to be formed when mixed with water?

• substance 1

• substance 2

• substance 3

• substance 4

Tags

NGSS.MS-PS1-2

Many processes occur in the digestive system. Which process is best classified as a physical change?

• Saliva converting the starch molecules in crackers into simple sugars.

• Digestive enzymes breaking down proteins into smaller fragments.

• Bacteria converting lactose into simple sugars in the intestines.

• Teeth grinding an almond into smaller pieces in the mouth.

A balance and a graduated cylinder are used to determine the density of a mineral sample. The sample has a mass of 14.7 g and a volume of 2.2 cm³. What is the density of the mineral sample?

• 0.15 g/cm³

• 32 g/cm³

• 13 g/cm³

• 6.7 g/cm³

A teacher asks a student to write the chemical equation for photosynthesis. The student's response is shown. The equation is not balanced correctly. Which of these is a balanced equation for photosynthesis?

• 12CO₂ + H₂O ------> C₆H₁₂O₆ + O₂

• CO₂ + 9H₂O ------> C₆H₁₂O₆ + O₂

• CO₂ + H₂O ------> 3C₆H₁₂O₆ + O₂

• 6CO₂ + 6H₂O ------> C₆H₁₂O₆ + 6O₂

Tags

NGSS.MS-LS1-6

NGSS.MS-LS2-3

Nitrogen dioxide is a gas that can be generated by emissions from vehicles and factories. It can also be generated by natural sources, such as forest fires, lightning, and microbial activity win soil. The equation for producing nitrogen dioxide is shown. Which of these provides evidence that a chemical reaction occurs?

• A gas is present

• The total number of atoms remains unchanged.

• The state of matter remains the same.

• A brown gas is produced.

Tags

NGSS.MS-PS1-2