Answer:
Copper turns green on exposure to air
Explanation:
Liquid water freezes to form ice: Physical change
Reason: Water can melt back when it becomes ice.
Copper turns green on exposure to air: Chemical change
Reason: The copper can not change back from the green state when it turns green.
Answer:
2.89 g/cm^3
Explanation:
Since density equals mass over volume (or also seen as 
), simply divide 66.5 grams by 23.0 cm. This will output an answer of 2.89 g/cm^3.
The ball travels 10m/s
Speed = distance/time
Answer: 0.405g
Explanation:
Molar Mass of Be = 9g/mol
Number of mole of Be = 0.045mol
Mass conc. Of Be = 0.045 x 9 = 0.405g
