5 moles of H2
..............
Answer:
The enthalpy of the reaction is 64.9 kJ/mol.
Explanation:
..[1]
..[2]
..[3]
..[4]
2 × [2] - [1]- [3] = [4] (Using Hess's law)



The enthalpy of the reaction is 64.9 kJ/mol.
Answer:
Answer: A) .346 M
Explanation:
Given:
- 450 mL
- .5 M soln
-200 mL water
1) Convert mL to L
450 mL = .45 L
200 mL = .2 L
2) Find mols in solution
.5 M = x/.45 L
x = .225 mol
3) Find total volume of solution
.45 L + .2 L =.65 L
4) Find new molarity
molarity (M) = mols solute/ L solution
y = .225 mol (from step 2)/ .65 L (from step 3)
y = .346 M
Answer: A) .346 M
Answer:
E. None of these
Explanation:
We know, By GAS laws,
PV = NRT, where p- pressure, v- volume, n- number of moles, R- gas constant ,and T- temperature
Now, In the question, the number of moles remains the same as the gas is the same. so n is constant so we can compare n before and after a temperature change.
= 
where P1= 1 atm, P2 = 10 atm, V1= 20 mL, T1= 10°C and T2= 100°C
We don't have to worry about the standard units as they are present equally on both the sides and get cut, same goes for R( gas constant)
So putting values, we get

Cutting, R on both sides and moving contents to the right so that only V2 is left on the left.

∴ V2 = 
∴ V2 = 20mL
12gHe/1 × 1molHe/4.0026g × 6.02x10^23atomHe/1mol = 1.8 atoms