Answer:
24.5 g of NaCl
Explanation:
We begin from the balanced reaction:
3MgCl₂ + 2Na₃PO₄ → 6NaCl + Mg₃(PO₄)₂
If the sodium phosphate is in excess, then the limting reagent is the magnessium chloride.
We convert mass to moles:
20 g . 1mol / 95.2g = 0.210 moles.
3 moles of MgCl₂ can produce 6 moles of NaCl
0.210 moles of salt, may produce (0.210 . 6) /3 = 0.420 moles
Ratio of reactant is twice the product
We convert the moles to mass:
0.420 mol . 58.45 g/mol = 24.5 g
0.042 moles of Hydrogen evolved
<h3>Further explanation</h3>
Given
I = 1.5 A
t = 1.5 hr = 5400 s
Required
Number of Hydrogen evolved
Solution
Electrolysis of water ⇒ decomposition reaction of water into Oxygen and Hydrogen gas.
Cathode(reduction-negative pole) : 2H₂O(l)+2e⁻ ⇒ H₂(g)+2OH⁻(aq)
Anode(oxidation-positive pole) : 2H₂O(l)⇒O₂(g)+4H⁻(aq)+4e⁻
Total reaction : 2H₂O(l)⇒2H₂(g)+O₂(g)
So at the cathode H₂ gas is produced
Faraday : 1 mole of electrons (e⁻) contains a charge of 96,500 C

Q = i.t
Q = 1.5 x 5400
Q = 8100 C
mol e⁻ = 8100 : 96500 = 0.084
From equation at cathode , mol ratio e⁻ : H₂ = 2 : 1, so mol H₂ = 0.042
Answer:
c. 0.750 atm
.
Explanation:
Hello!
In this case, since the two vessels have different volume, we can see that the gas is initially at 3.00 atm into the 1.00-L vessel, but next, it is allowed to move towards the 3.00-L vessel, meaning that the final volume wherein the gas is located, is 4.00 L; therefore, we use the Boyle's law to compute the final pressure:

Therefore the answer is c. 0.750 atm
.
Best regards!
Well depending on how many people on one side of the family, you would inherite their trait more commonly.
The molar mass is usually referred to with
M
, while the mass is referred to as
m
. The amount of substance is
n
. This gives you the following relationship:
=
M
=
m
n
Since you have given (C3H8)=11 g
m
(
C
3
H
8
)
=
11
g
and you already looked up (C3H8)=44.1 gmol−1
M
(
C
3
H
8
)
=
44.1
g
m
o
l
−
1
, you can use this formula to determine (C3H8)
n
(
C
3
H
8
)
.
In this question it is quite hard to explain the use of significant figures. Those are used to imply a certain inaccuracy. Not enough information is given by the question, as of how accurate the measurement is. It is a mere exercise of converting one property into another. Here you should not worry about it.