1st Semester Exam prep

Front

Which statement BEST describes the motion of water molecules as the water changes state from steam to liquid?

Back

The molecules move slower and occupy less space.

Front

When a mixture of oxygen and hydrogen is ignited in a test tube, what happens to the total mass?

Back

The total mass remains the same.

Front

Elements on the right side of the periodic table differ from the elements on the left side in that the elements on the right side?

Back

tend to form ions by gaining electrons.

Front

The difference between the atomic number of an element and the element’s atomic mass is the number of: ions, protons, neutrons, electrons

Back

neutrons

Front

What is the best visual evidence to show a chemical reaction is exothermic?

Back

Listing of temperatures of reactants and products

Front

Which is an indication that a chemical change is taking place?

Back

A gas forms when vinegar and baking soda are mixed.

Front

How does the concept of conservation of mass apply to chemical reactions?

Back

The reactants and products have exactly the same atoms.

Front

Which is a chemical change? the melting of the wax, the burning wick of the candle, the sugar dissolving in the tea, the steam coming from the tea

Back

the burning wick of the candle

Front

Which statement supports that a chemical reaction took place? Before: Iron filings are brown, small, and magnetic; copper sulfate crystals are blue, brittle, and not magnetic. After: The copper formed was reddish, solid, and not magnetic; iron sulfide solution was colorless and not magnetic.

Back

A new substance was formed.

Front

Which of these are broken down during chemical, but not physical, changes?

• elements
• mixtures
• solutions
• compounds

Back

compounds