Which involves a chemical change? filtering sand from water

distilling pure water from salt water

separating hydrogen and oxygen from water

evaporating sugar from sweetened water

Which notation is used to represent an alpha particle? a. b. c. d.

Which compound is held together by the electrostatic force between two ions? a. co2 b. cci4 c. h2s d. mgf2

An object with initial temperature 130 ∘ f is submerged in large tank of water whose temperature is 50 ∘ f . find a formula for f ( t ) , the temperature of the object after t minutes, if the cooling constant is k = − 0.2 . remember newton's law of cooling (the rate of change of temperature with respect to time is equal to k times the difference between the temperature of the object and the surrounding temperature) ! : )