Chemistry STAAR Review

Front

How many valence electrons are in an atom of each element in Group 15 in the periodic table?

Back

5

Front

Based on atomic models, which element is the least reactive? Options: Neon, Chlorine, Gallium, Tin

Back

Neon, because it has two energy levels with eight electrons in the second level

Tags

NGSS.MS-PS1-1

Front

Which statement accurately describes the atoms of a specific element?

Back

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

Tags

NGSS.MS-PS1-1

Front

Which chemical reaction involves the fewest oxygen atoms?

Back

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Front

As part of an investigation, students combined substances in a beaker to observe chemical reactions. They performed two procedures. They measured the mass of each substance before and after each reaction. The table shows their observations. Assuming the students did not make any careless errors, what likely explains these changes in mass?

• Procedure 1: One of the products was a gas that escaped into the air. Procedure 2: A gas from the air reacted with one of the other reactants.
• Procedure 1: The reactants were liquids with different densities. Procedure 2: The reactants were combined into only one product.
• Procedure 1: One of the reactants was converted to thermal energy. Procedure 2: All the products were liquids.
• Procedure 1: All the reactants were liquids that evaporated. Procedure 2: A gas was formed as one product, and it escaped into the air.

Back

Procedure 1: One of the products was a gas that escaped into the air. Procedure 2: A gas from the air reacted with one of the other reactants.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Front

Four students were asked to complete a table for a science assignment. Each student selected one chemical element from each of four groups in the periodic table and then classified each element as a metal, a nonmetal, or a metalloid. Which table was completed correctly?

Back

Tags

NGSS.MS-PS1-1

Front

Changes to food during digestion: Esophagus squeezes food into the stomach by wave-like muscle contractions. Peptidase enzymes in the small intestine break food molecules into smaller molecules.

Back

The muscle contractions result in physical changes, while the action of the peptidase results in chemical changes.

Tags

NGSS.MS-LS1-7

Front

Which statement does NOT correctly compare silicon with another element? Options: Silicon is a better conductor of electricity than sulfur. Silicon conducts electricity as well as copper does. Silicon is a solid at room temperature, but argon is a gas. Silicon is less malleable than silver.

Back

Silicon conducts electricity as well as copper does.

Tags

NGSS.MS-PS1-1

Front

Location and charge of electrons in an atom?

Back

The electrons are outside the nucleus and have a negative charge.

Front

The table lists some compounds found in foods and their formulas. Based on this information, which of these statements is NOT true?

• A molecule of sorbitol contains three more oxygen atoms than a molecule of glutamine does.
• A molecule of lactose contains twice as many atoms as a molecule of fructose does.
• A molecule of fructose contains four more atoms than a molecule of glutamine does.
• A molecule of lactose contains twice as many carbon atoms as a molecule of sorbitol does.

Back

A molecule of lactose contains twice as many atoms as a molecule of fructose does.

Tags

NGSS.MS-PS1-1