Chemistry Coach Murray

A student mixed two clear liquids together. The student can conclude that a chemical change occurred because

• the temperature of the substances was constant throughout the experiment.

• the total mass of the substances was constant throughout the experiment.

• some of the mixture changed into a different physical state.

• some of the mixture formed a material with different properties

Tags

NGSS.MS-PS1-2

Murray and Brenda performed an experiment where the clear solution X was added to the clear solution Y. The resulting mixture held a white solid. How is this possible?

• The atoms in the two solutions rearranged to form a new material with different properties.

• Mixing the two solutions caused part of the liquid to evaporate, leaving solids behind.

• Mixing the two solutions caused the temperature to drop, changing their states.

• The atoms in the two solutions all combined to form a new material with different properties.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

2H₃PO₄ + 3Ca(OH)₂ --->Ca₃(PO₄₎₂ + 6H₂O

Which are the reactants in the formula?

• Ca₃(PO₄₎₂ + 6H₂O

• Ca(OH)₂

• 2H₃ PO₄ + 3Ca(OH)₂

• Ca₃(PO₄₎₂

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

2H₃ PO₄ + 3Ca(OH)₂--->Ca₃(PO₄)₂+ 6H₂O

Which are the products in the formula?

• Ca₃(PO₄)₂

• Ca₃(PO₄)₂+ 6H₂O

• 2H₃ PO₄

• 2H₃ PO₄ + 3Ca(OH)₂

Tags

NGSS.MS-PS1-2

Sharon and Janet are doing an experiment to investigate the law of conservation of mass. They heat a solid in an open container and record the mass of the solid before and after heating. The mass before heating was 7.5 grams and 5.5 grams after heating.

Which best describes the conservation of mass in this experiment?

• The law of conservation of mass was not broken because the solid was heated in an open container, allowing gases to escape.

• The law of conservation of mass was broken in this experiment because the mass of the solid decreased.

• The law of conservation of mass was broken in this experiment because the solid was heated in an open container, allowing gases to escape.

• The law of conservation of mass was not broken because the mass before heating was greater than the mass after heating.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Robbie and Betsy are conducting an experiment. The mass of their candle before burning was 7.0 grams. After burning the candle for six minutes, the mass went down to 5.5 grams.

What can the students determine about the results of their experiment?

• The law of conservation of mass cannot be applied over short periods of time.

• The law of conservation of mass was broken because the mass of the candle decreased.

• The law of conservation of mass does not apply to chemical changes like burning.

• The law of conservation of mass was not broken because the missing mass was released as smoke.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Fe + CuSO₄ ----> FeSO₄ + Cu

Select all of the reactants in this reaction. (More than one)

• iron

• copper

• copper (II) sulfate

• iron (II) sulfate

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

Which statement supports the main ideas of the law of conservation of mass?

• The substances that take part in a chemical reaction are the same as the substances that are formed by the reaction.

• The masses of the substances that take part in a chemical reaction are greater than the masses of the substances formed by the reaction.

• The masses of the substances that take part in a chemical reaction are less than the masses of the substances that are formed.

• The masses of the substances that take part in a chemical reaction are equal to the masses of the substances that are formed

Tags

NGSS.MS-PS1-5

In a chemical reaction, table sugar (sucrose) is mixed with sulfuric acid. The result of the reaction is a towering black structure of elemental carbon, water vapor, carbon dioxide, and sulfur dioxide gases.

How can conservation of matter be proved using this reaction?

• The masses of the sugar, sulfuric acid, and glassware should be recorded before the experiment, then the energy lost can be added to the resultants and compared to the original masses.

• The masses of the sugar, sulfuric acid, and glassware should be recorded before the experiment, then the resulting reactant masses should be compared with the original masses.

• The masses of the resultant gases and structure should be weighed to show that the resultants are heavier than the products.

• The masses of the resultant gases and structure should be weighed to show that the resultants are lighter than the products.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

NaCl + H₂ SO₄ ----> NaHSO₄ + HCl

Which of the following best illustrates that matter is conserved in this chemical reaction?

• the sodium chloride and sodium bisulfate are both acids

• the hydrogen chloride is a gas

• the products and the reactants have the same number of atoms of each element

• the number of products is the same as the number of reactants

Tags

NGSS.MS-PS1-5