when a car is going downhill, the driver must apply more pressure on the brakes to stop than if the car were on level ground. wh
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Answer:
d.
Explanation:
Mass of calcium = 4.00 g
Molar mass of calcium = 40.078 g/mol
<u>Moles of calcium = 4.00 / 40.078 moles = 0.9981 moles</u>
Given that the compound only contains calcium and bromine. So,
Mass of bromine in the sample = Total mass - Mass of calcium
Mass of the sample = 20.0 g
<u>Mass of bromine in sample = 20.0 - 4.00 g = 16.0 g</u>
Molar mass of bromine = 79.904 g/mol
<u>Moles of Bromine = 16.0 / 79.904 = 0.2002 moles </u>
Taking the simplest ratio for Ca and Br as:
0.9981 : 0.2002 = 5 : 1
The empirical formula is =