Dmitri Mendeleev Was the name of the guy you where looking for
<span>Ca(NO3)2 + Na2CO3 = CaCO3 + 2NaNO3
Yes a precipitate of Calcium Carbonate is formed since it is insoluble in water.
Mol Wt of Calcium Nitrate is 164. And that of Calcium Carbonate is 100.
One mole of Calcium Nitrate produces one mole of Calcium Carbonate.
i.e. 164 gms will produce 100gms of precipitate
So, 1.74gms of Calcium Carbonate will be obtained from 2.85gms Calcium Nitrate present in the original solution.</span>
Answer:

Explanation:
Given that:

From equation (3) , multiplying (-1) with equation (3) and interchanging reactant with the product side; we have:

Multiplying (2) with equation (4) ; we have:

From equation (1) ; multiplying (-1) with equation (1); we have:

From equation (2); multiplying (3) with equation (2); we have:

Now; Adding up equation (5), (6) & (7) ; we get:



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(According to Hess Law)


Explanation:
Molar mass of HBr = 81 g/mol
Molar mass of nitrogen dioxide gas = 46 g/mol
Molar mass of ethane = 30 g/mol
Graham's Law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows the equation:

So, the gas with least molar mass will effuse out fastest from the container and that is ethane gas.
The formula for average kinetic energy is:

where,
k = Boltzmann’s constant = 
T = temperature = 273.15 K ( at STP)
As we can see from the formula that kinetic energy depends upon only temperature of the gas molecule.
So, from this we can say that all the gas molecules have the same average kinetic energy at this temperature.