To begin with, the equation given is not correct.
Correct equation is : CaCO3 + HCl ---> CaCl2 + H2O + CO2
It's CaCl2 not CaCl because Ca has a valency of 2
LHS RHS
CaCO3 + HCl ---> CaCl2 + H2O + CO2
First of all, to balance the equation you must look at the number of atoms on each side of the equation.
we have 2 H on the RHS and 1 H on the LHS. So, we put a 2 on the LHS
CaCO3 + 2HCl ---> CaCl2 + H2O + CO2
Check for the LHS: 1 Ca, 1 C, 3 O, 2 H & 2 Cl on the LHS
Now check for the RHS: 1 Ca, 2 Cl, 2 H, 1 C & 3 O
Hope it helped!
Answer: The partial pressure of oxygen in the mixture if the total pressure is 525 mmHg is 310 mm Hg
Explanation:
mass of nitrogen = 37.8 g
mass of oxygen = (100-37.8) g = 62.2 g
Using the equation given by Raoult's law, we get:

= partial pressure of
= ?

= total pressure of mixture = 525 mmHg


Total moles = 1.94 + 1.35 = 3.29 moles


Thus the partial pressure of oxygen in the mixture if the total pressure is 525 mmHg is 310 mm Hg
False
A heliocentric is when the model is
representing the sun as the center
A geocentric says the earth is at the center of the universe
Solution :
Molar mass of
is :
M = 6×12 + 6×1 g
M = 78 g
78 gram of
contains
molecules.
So, 89.5 gram of
contains :

Now, from the formula we can see that one molecule of
contains 2 hydrogen atom . So, number of hydrogen atom are :

Hence, this is the required solution.