Chemical Reactions

Which example provides evidence of a chemical change?

• Wood releases ash and smoke when burned.

• Rock particles separate when soil is being sifted.

• Boiling water bubbles when being heated.

• Sugar is not visible when dissolved in water.

Tags

NGSS.MS-PS1-2

Mixing silver nitrate and sodium chloride in water will cause silver chloride to precipitate out of solution. In this example, the precipitate is silver chloride. Which example represents the formation of a precipitate?

• Heat and light are produced when paper burns.

• White chunks form when you add vinegar to milk or heavy cream.

• Gas is released when vinegar and baking soda are mixed together.

• A cut apple turns brown when left out in the open air.

Tags

NGSS.MS-PS1-2

When vinegar and baking soda are combined, bubbles and foam are produced.

What evidence demonstrates that a chemical change has occurred?

• A color change occurs.

• A gas is formed.

• A solid is dissolved.

• A precipitate is formed.

Tags

NGSS.MS-PS1-2

Which processes from the table can be used as evidence to identify the formation of a new substance?

• Processes A, B, C, and D

• Processes B, C, E, and F

• Processes B, C, D, and F

• Processes C, D, E, and F

Tags

NGSS.MS-PS1-2

Students performed investigations using water and three chemicals, baking soda, calcium chloride, and phenol red solution.  The student observations are shown in the table.

Which investigations above provide supporting evidence that a new substance formed?

• Investigations 1, 2, and 3

• Investigations 1, 3, and 5

• Investigations 2, 3, and 4

• Investigations 3, 4, and 5

Tags

NGSS.MS-PS1-2

After an investigation, students were disposing of left over substances.  One student poured all of the liquids down the sink drain.  A few seconds later, a white cloud formed above the sink and the student’s eyes began to burn.

Which statement accurately describes what caused this occurrence?

• The student did not wait two minutes in between pouring each liquid down the drain.

• The student did not allow water to run in the sink after pouring each liquid down the drain.

• A physical change occurred resulting in the formation of a new substance.

• A chemical change occurred resulting in the formation of a new substance.

Tags

NGSS.MS-PS1-2

Students performed multiple investigations at different stations in the classroom.  The data collected is listed in the table.

The observations from which investigations provide evidence that a new substance was formed?

• Stations 1, 3, 4, and 5

• Stations 2, 5, and 6

• Stations 1, 3, and 4

• Stations 1, 2, 3, and 4

Tags

NGSS.MS-PS1-2

Table salt is a compound made from two elements, sodium and chlorine.

Which statement best explains why the characteristics of table salt are so different from the characteristics of sodium and chlorine?

• Salt is processed by the evaporation of seawater or mineral-rich spring water

• Salt is processed from salt mines because pure sodium does not occur in na

• When sodium and chlorine combine, a physical change occurs and a new substance is formed.

• When sodium and chlorine combine, a chemical change occurs and a new substance is formed.

Tags

NGSS.MS-PS1-2

Students performed an investigation to see what would happen when sugar is exposed to heat. The students' observations are listed in the table.

Which students’ observations indicate that a new substance formed as a chemical change occurred?

• Student A and Student C

• Student B and Student C

• Student A and Student D

• Student B and Student D

Tags

NGSS.MS-PS1-2

Flour, sugar, cocoa, oil, and eggs are mixed together and placed in the oven to make brownies.  When the brownies are removed from the oven, they no longer look like the original ingredients. 

Which of the following describes why the ingredients changed?

• A biological change occurred.

• No change occurred.

• A physical change occurred.

• A chemical change occurred.

Tags

NGSS.MS-PS1-2

NGSS.MS-LS1-7