In this question we need to find the new volume of the gas. Since we have been given the pressure and temperature change, we can used to combined gas law equation.

the parameters for 1st instance are given on the left side and parameters for the second instance are given on the right side of the equation
(319 mmHg x 0.558 L)/ 115 K = (215 mmHg x V)/387 K
V = 2.79 L
Answer:
Upper F subscript 2 (g) plus upper C a (s) right arrow with delta above upper C a upper F subscript 2 (s).
Explanation:
This is a chemical reaction problem.
In expressing any chemical reaction, we need to understand that there are reactants and products.
- The reactants are the species on the left hand side that are combining.
- The products are the species on the right hand side that are formed.
- Every chemical reaction is obeys the law of conservation of matter i.e equal number of matter on both sides.
Using the statement of this problem, we can deduce that;
Reactants are Fluorine gas and Calcium metal
Product is Calcium Fluoride
Note: A metal is a solid(s) and powder is a solid(s). A gas is denoted as (g). They depict the state of the species reacting.
F₂
+ Ca
→ CaF₂
We can see that equal number of atoms are on both sides of the expression.
Answer:
About 0.08486 moles
Explanation:
PV=nRT, when P is the pressure in atmospheres, V is the volume in liters, n is the number of moles, R is the universal gas constant, and T is the temperature in Kelvin.

moles
Hope this helps!
The trick for this problem is to understand atomic mass: the fact that different atoms have different masses. What we need to do is add up all the atomic masses of the compound and work out the ratio of mass of water to the mass of sodium carbonate. Atomic masses are often given for each atom in the periodic table, but you can look them up on google too.
You can do this by adding up individual atoms for each molecule, or you can shortcut and lookup the molar mass of the compound (i.e.the task already done for you).
The molar mass of water is 18.01g/mole so for 10 moles of water we have a mass of 180.1g.
The molar mass of sodium carbonate is 106g/mole (google).
So the total mass of the sodium carbonate decahydrate compound is 180.1+106 = 286.1g, of which water would make up 180.1g, so the percentage of water is is 180.1/286.1 = 0.629, so we can round this to 63%
:)