In the diagram to the right, the battery provides 12 V to the circuit made up of three identical light bulbs. When the switch is
closed the voltage across bulb A will be
A. 12 V.
B. 2 V.
C. 6 V.
D. 4 V.
A. 12 V.
B. 2 V.
C. 6 V.
D. 4 V.
1 answer:
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Answer:
0.17%
Explanation:
With the equation:
2Cr2O7 2- + C2H5OH + H2O --> 4Cr3+ + 2CO2 + 11H2O
We can assume that every mole of ethanol needs 2 moles of Dichromate to react.
So if in 1L we have 0.05961 moles of dichromate we can discover how many moles we have in 35.46mL
1000 mL - 0.05962 moles
35.46 mL - x
x =
x = 2,11* 10^-3 moles
As we said earlier, 1 mole of ethanol needs 2 mole of dichromate, so in the solution we have 1,055*10^-3 moles of ethanol. We can discover the mass of ethanol present in the solution.
1 mole - 46g
1.055*10^-3 - y
y = 46 * 1.055*10^-3
y = 0.048 g
To discover the percent of alchol we can use a simple relation
28 g - 100%
0.048 - z
z =
z = 0.17%
Answer:
4. 1.18 mol·L⁻¹
14. See below.
Explanation:
4. Dilution calculation
V₁c₁ = V₂c₂
Data:
V₁ = 200 mL; c₁ = 5.6 mol·L⁻¹
V₂ = 950 mL; c₂ = ?
Calculation:
c₂ = c₁ × V₁/V₂
c₂ = 5.6 mol·L⁻¹ × (200/950) = 1.18 mol·L⁻¹
The new concentration is 1.18 mol·L⁻¹ .
14. Boyle's Law graphs
We can write Boyle's Law as
pV = k or p = k/V or V= k/p
p and V are inversely related.
(a) As pressure increases, volume decreases. Thus, a graph of V vs p is a hyperbola.
(b) p = k/V =k(1/V)
1/V = (1/k)p
y = m x + 0
A graph of 1/V vs p is a straight line.
