Lesson Worksheet: Conservation of Elements Chemistry
In this worksheet, we will practice describing the conservation of elements during chemical reactions.
Which of the following statements best describes the conservation of elements during a chemical reaction?
- ANo element can appear or disappear during a chemical reaction.
- BElements can disappear but not appear during a chemical reaction.
- CElements can appear but not disappear during a chemical reaction.
- DElements can appear or disappear during a chemical reaction.
By using the concept of conservation of elements, identify the element missing in the following chemical equation:
Students combine concentrated nitric acid with copper metal and observe a vigorous chemical reaction. They notice a color change and effervescence as copper metal transforms into a copper nitrate product. What is the name of the gas this chemical reaction process produces?
- ANitrogen dioxide
- BElemental oxygen
- CElemental nitrogen
- DNitrous acid
- ENitric oxide
A pale blue precipitate forms when copper(II) sulfate reacts with sodium hydroxide. What is the identity of the precipitate?
- ASodium copper sulfate
- BCopper(III) hydroxide
- CCopper oxide
- DSodium sulfate
- ECopper(II) hydroxide
Magnesium reacts explosively with oxygen to form magnesium oxide according to the following equation:
Which of the following is not true of this reaction?
- AMagnesium oxide has similar physical and chemical properties to both oxygen and magnesium.
- BThe reactants, magnesium and oxygen, are elements.
- CThe concept of conservation of elements is obeyed.
- DThe product of the reaction, magnesium oxide, is a compound.
- EThe reaction describes the formation of a new substance.
A student heats a mixture of copper(II) oxide and carbon. They produce carbon dioxide and a reddish-orange solid. What is the identity of the reddish-orange solid?
- ACopper carbonate
- BCopper dioxide
- CCopper metal
- DCopper(III) oxide
- ECopper trioxide