Explanation:
Moles of metal,
=
4.86
⋅
g
24.305
⋅
g
⋅
m
o
l
−
1
=
0.200
m
o
l
.
Moles of
H
C
l
=
100
⋅
c
m
−
3
×
2.00
⋅
m
o
l
⋅
d
m
−
3
=
0.200
m
o
l
Clearly, the acid is in deficiency ; i.e. it is the limiting reagent, because the equation above specifies that that 2 equiv of HCl are required for each equiv of metal.
So if
0.200
m
o
l
acid react, then (by the stoichiometry), 1/2 this quantity, i.e.
0.100
m
o
l
of dihydrogen will evolve.
So,
0.100
m
o
l
dihydrogen are evolved; this has a mass of
0.100
⋅
m
o
l
×
2.00
⋅
g
⋅
m
o
l
−
1
=
?
?
g
.
If 1 mol dihydrogen gas occupies
24.5
d
m
3
at room temperature and pressure, what will be the VOLUME of gas evolved?
Answer:
Explanation:
The density formula is mass over volume.
Rearrange the formula for the mass, m. Multiply both sides of the formula by v.
Mass can be found by multiplying the density and volume. The density is 0.65 grams per milliliter and the volume is 45.0 cubic centimeters.
- A cubic centimeter is equal to a milliliter.
- Therefore, 45 cubic centimeters also equals 45 milliliters.
Substitute the values into the formula.
Multiply. Note the milliliters, or mL will cancel out.
The mass of the wood is 29.25 grams.
Answer:
0
Explanation:
Given parameters:
Half-life = 8.08days
Unknown:
What fraction is left unchanged after 16.16days = ?
Solution:
The half - life of a substance is the time taken for the half of a radioactive material to decay to half.
Day 0 Day 8.08 Day 16.16
100% 50% 0% Parent
0% 50% 100% Daughter
After 16.16 days, non of the original sample will remain unchanged.
Answer:
Two water molecules contain 4 hydrogen atoms and 2 oxygen atoms. A mole of water molecules contains 2 moles of hydrogen atoms and 1 mole of oxygen atoms.
Explanation:
Answer: The concentration of hydrogen ion in the given solution is 
.
Explanation:
pOH of a solution is the negative logarithm of concentration of hydroxide ions.
Hence, if ![[OH^{-}]](https://tex.z-dn.net/?f=%5BOH%5E%7B-%7D%5D)
is 
then its pOH value is calculated as follows.
![pOH = -log [OH^{-}]\\= -log (3.5 \times 10^{-5})\\= 4.45](https://tex.z-dn.net/?f=pOH%20%3D%20-log%20%5BOH%5E%7B-%7D%5D%5C%5C%3D%20-log%20%283.5%20%5Ctimes%2010%5E%7B-5%7D%29%5C%5C%3D%204.45)
Now, the relation between pH and pOH is as follows.
pH + pOH = 14
pH + 4.45 = 14
pH = 14 - 4.45
= 9.55
And, pH is the negative logarithm of concentration of hydrogen ions. Hence, ![[H^{+}]](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%5D)
is calculated as follows.
![pH = -log [H^{+}]\\9.55 = -log [H^{+}]\\H^{+} = 2.81 \times 10^{-10}](https://tex.z-dn.net/?f=pH%20%3D%20-log%20%5BH%5E%7B%2B%7D%5D%5C%5C9.55%20%3D%20-log%20%5BH%5E%7B%2B%7D%5D%5C%5CH%5E%7B%2B%7D%20%3D%202.81%20%5Ctimes%2010%5E%7B-10%7D)
Thus, we can conclude that the concentration of hydrogen ion in the given solution is .
