End of Unit 1 Retest!

An equation for a chemical reaction is shown. NaOH + HCl → NaCl + H₂O Which statement evidence that mass is conserved in the reaction?

• Two new substances are formed in the products.

• Water is one of the products, but not one of the reactants.

• One chlorine atom pairs with one sodium atom in the products, and one chlorine atom pairs with one hydrogen atom in the reactants.

• Two hydrogen atoms are in the reactants, and two hydrogen atoms are in the products.

Tags

NGSS.MS-PS1-5

When calcium carbonate (CaCO₃) is heated, it decomposes  to form calcium oxide(CaO) and carbon dioxide (CO₂). The equation below shows this reaction.

CaCO₃    →    CaO + CO₂

Reactant           Products

In this reaction, the mass of CaCO₃-

• is less than the mass of CaO plus the of CO₂

• is greater than the mass of CaO plus the mass of CO2

• equals the mass of CaO plus the mass of CO2

• equals the mass of CaO minus the mass CO2

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Two solutions are mixed and react to produce the solid precipitate AgCl. The chemical reaction is shown by the balanced chemical equation. AgNO₃ + NaCl → AgCl + NaNO₃ What happens to the total mass as the reaction takes place?

• The mass first decreases and then increases.

• The mass remains constant.

• The mass increases.

• The mass decreases.

Tags

NGSS.MS-PS1-5

A chemical equation for the reaction between calcium hydroxide, Ca(OH)2, and sulfuric acid, H2SO4, is shown. The masses of some of the reactants and products are given in grams.

        

How many grams of sulfuric acid were used in the reaction?

             

Mathematical Equivalence

ON

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

During photosynthesis, carbon dioxide and water are into glucose and oxygen. How does the number of atoms of each element change in this reaction?

• The number of atoms of each element changes because glucose is formed.

• The number of atoms of each element decrease as they are used up.

• The number of atoms of each element is unpredictable because new substances are formed.

• The number of atoms of each element remains the same after the reaction.

Tags

NGSS.MS-LS1-6

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The chemical formula for methane is CH₄.

Which statement describes the atoms present in FOUR molecules of methane?

• Four molecules of methane would contain 4 atoms of carbon and 16 atoms of hydrogen.

• Four molecules of methane would contain 1 atom of carbon and 4 atoms of hydrogen.

• Four molecules of methane would contain 4 atoms of carbon and 1 atom of hydrogen.

• Four molecules of methane would contain 16 atoms of carbon and 16 atoms of hydrogen.

Tags

NGSS.MS-PS1-1

Oxygen and oxygen-containing compounds are involved in many different reactions. Which balanced equation represents a reaction that involves 14 atoms of oxygen?

• NH₄Cl + KOH → NH₃ + H₂O + KCl

• 2Na + 2H₂O → 2NaOH + H₂

• 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

• 4Fe + 3O₂ → 2Fe₂O₃

Tags

NGSS.MS-PS1-5

The names and chemical formulas of four substances are shown in the chart.

Which substance listed in the chart is made up of the most atoms?

• Carbonic acid

• Nitric acid

• Phosphoric acid

• Sulfuric acid

Tags

NGSS.MS-PS1-1

Barium sulfate, BaSO₄, is a white crystalline solid that is insoluble in water. It is used by doctors to diagnose problems with the digestive system. Barium hydroxide, Ba(OH)₂, is also a white crystalline solid and is used in wastewater treatment.

How many more oxygen atoms are in the formula for barium sulfate than in the formula for barium hydroxide?

• 2

• 4

• 3

• 1

Tags

NGSS.MS-PS1-1

Sodium sulfate (Na₂SO₄) is used in many products. Which elements are represented in the formula AND how many atoms of each element are represented in the formula? Fill in the blank: The element represented by 'Na' is _______.

• sodium

• nitrogen

• silver

• neon

Tags

NGSS.MS-PS1-1