The mixture contains:
CaCO3 + (NH4)2CO3 in which the amount of carbonate CO3 = 60.7% by mass
Let, the total mass = 100 grams
Mass of CaCO3 = x grams
Mass of (NH4)2CO3 = y grams
Thus, x + y = 100 ------------(1)
Mass of CO3 = 60.7% = 60.7 g
Molar mass of CO3 = 60 g/mol
Total # moles of CO3 = 60.7 g/60 g.mol-1 = 1.012 moles
The total moles of CO3 comes from CaCO3 and (NH4)2CO3. Therefore,
moles CaCO3 + moles (NH4)2CO3 = 1.012
mass CaCO3/molar mass CaCO3 + mass (NH4)2 CO3/molar mass = 1.012
x/100 + y/96 = 1.012---------(2)
based on equation 1 we can write: y = 100-x
x/100 + (100-x)/96 = 1.012
x = 71.2 g
Mass of CaCO3 = 71.2 g
Answer:
Option b, The change in free energy of the reaction (ΔG)
Explanation:
Gibbs free energy is a measure of amount of usable energy in the system.
It is related with enthalpy (H), entropy (S) and temprature (T) as:
G = H - TS
The Gibbs free energy change (ΔG) provide spontaneity of a chemical reaction.
If ΔG is negative, then reaction is spontaneous that means reaction is moving towards forward direction.
If ΔG is positive, then reaction is non-spontaneous that means reaction is moving in backward direction.
If ΔG is zero, then reaction is at equilibrium.
Change in enthalpy only gives informtion about heat involed in a chemical reaction, it does not give information about direction of the reaction.
So, among the given options, option b is correct.
5e earth holds many answers to things we don’t know about.
<u>Answer:</u> D. the ionic compound calcium fluoride 
The correct option here is the fourth one.
<u>Explanation:</u>
Salt like compounds addition to water is likely to be inducing certain changes in temperature of freezing into solid and also alter the temperature of boiling.
It is noticed that addition of salts in water mostly tends to get lower the freezing temperatures from the original freezing point of water and among the given 3 options calcium fluoride tends to lower the freezing point most when compared to others.
Thus as vant hoff factor is highest factor for 
and the freezing point will be lowest.
