Answer:
2NaCN + CaCO3 --> Na2CO3 + Ca(CN)2
Explanation:
Knowing the names gets us: NaCN + CaCO3 --> Na2CO3 + Ca(CN)2
Balance: there are two sodiums and cyanides on the product side so add a 2 to the reactant side.
Answer:
C.) 35
Explanation:
The mass is made up of the total protons and neutrons in an atom. Protons and neutrons both have a mass of 1 amu. Electrons are not included in this measurement because they have an insignificant mass (practically 0).
(17 protons x 1 amu) + (18 neutrons x 1 amu) = 35 amu
Therefore, if an atom contains 17 protons and 18 neutrons, the mass should be 35 amu.
The temperature is gonna be
Answer: Mass Of CFC that needs to evaporate for the freezing of water = 328.24 g
Explanation: Heat gained by the CFC = Heat lost by water
Heat lost by water = Heat required to take water's temperature to 0°c + Heat required to freeze water at 0°c
Heat required to take water's temperature from 33°c to 0°c = mCΔT
m = 201g, C = 4.18 J/(gK), ΔT = 33
mCΔT = 201 × 4.18 × 33 = 27725.94 J
Heat required to freeze water at 0°c = mL
m = 201g, L = 334 J/g
mL = 201 × 334 = 67134 J
Heat gained by CFC to vaporize = mH = 27725.94 + 67134 = 94859.94 J
H = 289 J/g, m = ?
m × 289 = 94859.9
m = 328.24 g
QED!!
