Answer:
0.868M Cu⁺
Explanation:
The reaction is:
KMnO₄ + 5Cu⁺ + 8H⁺ → 5Cu²⁺ + Mn²⁺ + K⁺ + 4H₂O
<em>Where 1 mol of KMnO₄ reacts with 5 moles of Cu⁺</em>
<em />
3.30x10⁻²L of 0.132M KMnO₄ are:
3.30x10⁻²L × (0.132mol KMnO₄ / L) = <em>4.356x10⁻³mol KMnO₄</em>
As 1 mol reacts with 5 moles of Cu⁺, moles of Cu⁺ are:
4.356x10⁻³mol KMnO₄ × (5mol Cu⁺ / 1mol KMnO₄) = <em>0.02178moles Cu⁺</em>
As these moles are in 2.51x10⁻²L, the starting concentration of the Cu⁺ solution is:
<em>0.02178moles Cu⁺ / </em>2.51x10⁻²L = <em>0.868M Cu⁺</em>
1. Exothermic, because it’s giving off heat
2. Exothermic, because it’s giving off heat
3. Endothermic, because it’s losing heat
Answer:
Molar concentration of HCl = 0.279 M
Explanation:
Given data:
Volume of NaOH = 31.00 mL ( 31/1000 = 0.031 L)
Molarity of NaOH = 0.0900 M
Volume of HCl = 10.00 mL (0.01 L)
Molar concentration of HCl = ?
Solution:
Chemical equation:
NaOH + HCl → NaCl + H₂O
Number of moles of NaOH:
Number of moles = Molarity × volume in L
Number of moles = 0.0900 mol/L × 0.031 L
Number of moles = 0.00279 mol
For one mole of HCl one mole of NaOH is required.
Number of moles of HCl = 0.00279 mol
Molar concentration of HCl = 0.00279 mol / 0.01 L
Molar concentration of HCl = 0.279 M
95.6 cal
are needed.
Explanation:
Use the following equation:
q
=
m
c
Δ
T
,
where:
q
is heat energy,
m
is mass,
c
is specific heat capacity, and
Δ
T
is the change in temperature.
Δ
T
=
T
final
−
T
initial
Known
m
=
125 g
c
Pb
=
0.130
J
g
⋅
∘
C
T
initial
=
17.5
∘
C
T
final
=
42.1
∘
C
Δ
T
=
42.1
∘
C
−
17.5
∘
C
=
24.6
∘
C
Unknown
q
Solution
Plug the known values into the equation and solve.
q
=
(
125
g
)
×
(
0.130
J
g
⋅
∘
C
)
×
(
24.6
∘
C
)
=
400. J
(rounded to three significant figures)
Convert Joules to calories
1 J
=
0.2389 cal
to four significant figures.
400
.
J
×
0.2389
cal
1
J
=
95.6 cal
(rounded to three significant figures)
95.6 cal
are needed.
Answer:
6 moles
Explanation:
You have a 1:3 ratio between nitrogen gas and hydrogen gas