1) Which two elements make up hydrocarbons? a) A. Carbon and hydrogen b) B. Carbon and oxygen c) C. Hydrogen and oxygen d) D. Nitrogen and carbon 2) During a small, teacher-supervised combustion test the teacher collects a black deposit on filter paper. Which conclusion follows best from this observation? a) A.The sample contains metal. b) B. The sample probably contains carbon (soot). c) C. The sample is pure water. d) D. The sample has significant oxygen content. 3) When the teacher placed a burning candle under a clear jar, tiny water droplets appeared on the jar interior. What does this most directly indicate? a) A. The jar was dirty. b) B. Burning produced water, which means hydrogen is present in the original substance. c) C. Burning removed oxygen from the air. d) D. The candle is made of sugar. 4) Which behavior is MOST consistent with a substance that is a hydrocarbon? a) A. Mixes readily with water and burns with a blue, clean flame. b) B. Does not mix with water and burning produces yellow, sooty flame and droplets of condensation. c) C. Dissolves in water and produces an acidic solution. d) D. Evaporates with a sweet smell and leaves no residue when burned. 5) Why do hydrocarbons usually not mix with water? a) A. Hydrocarbons are polar; water is nonpolar. b) B. Hydrocarbons are ionic; water is polar. c) C. Hydrocarbons are nonpolar while water is polar (like dissolves like). d) D. Hydrocarbons are heavier than water.

G9

列印
嵌入

排行榜

視覺風格

選項

切換範本

恢復自動保存: ?