L7-L10 Assessment

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Front

Did a chemical reaction occur when magnesium was burned? Select the best explanation.

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A chemical reaction occurred when the teacher burned magnesium. While the two solids have the same solubility, the magnesium (the solid before burning) has a different color, hardness, density, and melting point than the solid after burning. The products of a chemical reaction are different substances from the reactants. The properties of the solids are different, so a chemical reaction occurred.

Front

Look at the symbols for magnesium, oxygen, and magnesium oxide. Which model best represents the chemical reaction of the burning of magnesium? Magnesium: Mg Oxygen: O2, Magnesium oxide: 2MgO

Back

Model 1 is the most accurate.

Front

Does acid rain make new substances? Construct an argument that uses data from this investigation as evidence for your claim.

Back

A chemical reaction occurred when I combined the copper square and vinegar. The copper square before the experiment had a different color, hardness, solubility in water, density, and melting point from the solid on the copper square after the experiment. The properties of the solids before and after the experiment are different, so the solids are different substances. A chemical reaction always results in different substances.

Front

What is the best definition of a chemical reaction based on our current understanding? Options: A chemical reaction is a process when two or more substances interact and their atoms combine in new ways to form new substances with different properties than the old substances. The new substances are made of the same atoms as the old substances, but the atoms are arranged in new ways., Sometimes in a chemical reaction, a new substance is formed and energy is released., A chemical reaction is a process in which substances interact to form new substances with properties different from the old substances., A chemical reaction is a process when two or more substances interact and new substances are made with new atoms and molecules. The old atoms and molecules are absorbed into the surroundings.

Back

A chemical reaction is a process when two or more substances interact and their atoms combine in new ways to form new substances with different properties than the old substances. The new substances are made of the same atoms as the old substances, but the atoms are arranged in new ways.

Front

What were the reactants and products in the electrolysis of water?

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The reactant was water and the products were hydrogen gas and oxygen gas.

Front

Which argument could convince someone else that electrolysis is a chemical reaction? A chemical reaction occurred during electrolysis. We started with just liquid water, and after electrolysis, we had hydrogen gas and oxygen gas. We saw bubbles during the experiment that was an indication gas was being formed. We saw that one test tube had twice as much gas as the other test tube. During a flame test, one gas popped and the other caused a match flame to glow more brightly. The molecules of the water were split apart during electrolysis and the atoms rearranged to form hydrogen and oxygen gas. These two gases are new substances that have different properties than water.

Back

A chemical reaction occurred during electrolysis, resulting in the formation of hydrogen gas and oxygen gas, which are new substances with different properties than water.

Front

Which ball and stick model represents the process of the electrolysis of water as a chemical reaction?

Back

Model 1 because two water molecules broke down into two hydrogen molecules each with two hydrogen atoms and one oxygen molecule with two oxygen atoms.

Front

What must happen to the atoms and molecules of the drink solution for this to be a chemical reaction?

Back

The atoms in the water and powder must rearrange in new and different ways to form a new substance.