Answer:
appx. 1.07 moles
Explanation:
175g of molecule Ca(NO3)2
To find the # of moles, use stoichoimetry.
1. We need the molar mass of Ca(NO3)2.
Ca mass: 40.08 g
NO3 mass: N + 3(O) --> 14.01 + 3(16.00) --> 62.01
Molar mass = Ca + 2(NO3) --> 40.08 + 2(62.01) --> 164.1 g
2. write out the calculation
175g Ca(NO3)2 * (1 mole Ca(NO3)2)/(molar mass of Ca(NO3)2)
175 g Ca(NO3)2 * (1 mole Ca(NO3)2)/(164.1 g Ca(NO3)2)
The g units cancel out and we're left with moles.
Simply perform the calculation now: 175*1/164.1 ≅1.07 moles
The answer should be (D) Ca, because all others either occur as diatomic or are anions.
Answer:
Density changes with temperature because volume changes with temperature. Density is mass divided by volume. As you heat something up, the volume usually increases because the faster moving molecules are further apart. Since volume is in the denominator, increasing the volume decreases the density.
Explanation:
Density = mass/volume
density = 81 grams/0.9 cubic centimetersdensity = 90 grams per cubic centimeter
The density of the sample is 90 grams per cubic centimeter.
