EOC Science 7B Review

Choose the answer where a chemical reaction has not taken place.

• cooked eggs

• boiling water

• browning marshmallow

• grow seeds

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which method of testing substances is a sure way to identify a chemical reaction?

• change in color

• formation of bubbles

• change in density

• increase in temperature

• solubility in water

Tags

NGSS.MS-PS1-2

Classify the sentence based on the chemical reactions they describe. A strip of magnesium (Mg)

burns brightly in

oxygen (O₂) to form

a white powder,

magnesium oxide (MgO)

• Synthesis

• decomposition

• Replacement

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

2NaOH + H₂SO₄ → Na₂SO₄ + H₂O

The equation is ______________

because the number of hydrogen atoms and __________ atoms is ____________ in the reactants and in the products.

• not balanced, oxygen, not equal

• balanced, sodium, equal

• not balanced, sodium, not equal

• balanced, oxygen, equal

Tags

NGSS.MS-PS1-5

The equation shows neutralization of an acid and a base to produce a salt and water.

2HCl + Na₂O → xNaCl + H₂O

Which value of x will balance the equation?

• 1

• 2

• 4

• 3

Tags

NGSS.MS-PS1-5

In this equation, grey stands for carbon, blue stands for nitrogen, and red stands for oxygen. Which equation represents this reaction?

• 2CO + 2NO → 2CN₂ + O₂

• CO + NO → 2CO₂ + 2N₂

• 2CO₂ + 2NO → CO₂ + N₂

• 2CO + 2NO → 2CO₂ + N₂

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which changes will increase the rate of reaction during combustion? two changes.

• decreasing the area of contact between the reactants

• adding more oxygen to the reaction

• removing heat from the reaction

• changing the reactants from solid form to powdered form

• lowering the exposure of the reactants to air

Which chemical reaction absorbs energy?

• photosynthesis

• explosion

• current produced by a battery

• combustion of fuels

• activated hand warmers

Tags

NGSS.HS-PS1-4

Identify the types of chemical reactions occurring in the chemical equations.

glucose + oxygen → carbon dioxide + water + energy

• respiration

• photosynthesis

• combustion reaction of fossil fuels

Tags

NGSS.MS-LS1-6

Steel is an alloy of _________. One of the main reasons steel is used more widely than iron is because it’s ___________ than iron.

• copper, lighter

• iron, stronger

• silver, softer

• lead, maliable