Q: What is extracted from rock by heap leaching, flotation, or smelting? Choices: - methane - copper - fuel - ore A:
ore
------
Q: How many valence electrons can be found in a carbon atom? Choices: - five - three - One - four A:
four
------
Q: What are carbonated beverages pressurized with? Choices: - helium - dioxide - hydrogen - co2 A:
co2
------
Q: Hfcs are used as a replacement for what? Choices: - nitrofluorocarbons - pollutants - gases - cfcs A:
cfcs
------