A parallel-plate capacitor has capacitance 4.50 μF.

(a) How much energy is stored in the capacitor if it is connected to a 8.00-V battery?
μJ

(b) If the battery is disconnected and the distance between the charged plates doubled, what is the energy stored?
μJ

(c) The battery is subsequently reattached to the capacitor, but the plate separation remains as in part (b). How much energy is stored?
μJ

Two point charges Q₁ = +4.00 nC and

Q₂ = −2.70 nC

are separated by 55.0 cm.

(a) What is the electric potential at a point midway between the charges?
V

(b) What is the potential energy of the pair of charges?
J

What is the significance of the algebraic sign of your answer?

Positive work must be done to separate the charges.Negative work must be done to separate the charges.  

After several months of negotiations, the CEO of BIG Pty Ltd made the long-awaited announcement to board members that BIG Pty Ltd would be buying Melbourne based company, YAY Pty Ltd for $25m. The following persons were present at the meeting: Helen and Liam (Company Directors) and Tammy (Receptionist taking meeting minutes). News of the take-over would not be released to the public until the following week.
(a) Assume Helen owns 50,000 shares in YAY Pty Ltd . Discuss whether she would be breaching any duties if she makes a secret profit of $500,000 from the takeover. What can Helen do to avoid breaching any duties?

answer structure

Issue: Whether Helen would breach any duties…
Rule: According to Hospital Products Ltd v US Surgical Corp…
Furthermore: According to Aberdeen Railway Co v Blaikie Bros…
Analyze: Here, the facts tell us…
Conclusion: Clear that Helen would be breaching Duty __   … (remember to also mention what she can do to avoid the breach)

Consider the following figure. A hexagon has six labeled vertices and a dashed line segment which divides the hexagon into a trapezoid and rectangle. The first side is horizontal, starts at vertex R, goes to the right, and ends at vertex S. The second side is vertical, starts at vertex S, goes up, and ends at vertex T. The third side starts at vertex T, goes up and to the right, and ends at vertex V. The fourth side is horizontal, starts at vertex V, goes to the left, and ends at vertex W. The fifth side starts at vertex W, goes down and to the right, and ends at vertex X. The sixth side is vertical, starts at vertex X, goes down, and ends at vertex R. ∠R and ∠S are right angles. A dashed line segment connects vertex X to vertex T. The trapezoid is created above the segment and the rectangle below the segment. Given: hexagon RSTVWX with WV ∥ XT ∥ RS RS = 10 ST = 6 TV = 10 WV = 22 WX ≅ VT Find: ARSTVWX in square units

The cell Ag(s), AgI(s)|KI(10−2M)||KCl(10−3M)|Cl2(g,1bar), Pt(s) has the voltage 1.5702 V at 298 K.

Part A

Write the cell reaction.

Express your answer as a chemical equation. Identify all of the phases in your answer.

Part B

What is ΔrG at 298 K?

Express your answer to five significant figures and include the appropriate units.

Part C

What is ΔG∘ at 298 K?

Express your answer to three significant figures and include the appropriate units.

Part D

Calculate the standard reduction potential for the half-cell on the left.

Express your answer to three significant figures and include the appropriate units.

Part E

Calculate the solubility product of AgI:
KAgI=aAg+aI−

Express your answer using two significant figures.

Part F

The cell has a potential of 1.5797 V at 288 K. Estimate ΔrS at 298 K for the reaction.

Express your answer to two significant figures and include the appropriate units.

A metallic wire of length L and diameter d is covered with a very thin isolating layer. The resistivity of the metal is ρ (rho) and the wire has resistance R. When a battery with voltage V is connected to the ends of the wire a current I flows through it.

a)Find an equation for the resistivity ρ (rho) in terms of the variables provided.

b)For a wire of length 24.5 m and diameter 0.5 mm, calculate the resistivity (in Ωm) assuming that the current is 4.5 A when a 9-V battery is connected to the wire.

c)Write an equation for the power and calculate its value.

d)As current flows the wire heats up. How does this affect the resistance of the wire and the power, assuming the wire stays connected to the same battery.

a)The resistance increases and the power increases.

b)The resistance decreases and the power increases.

c)The resistance increases and the power decreases.

d)The resistance decreases and the power decreases.

e) The wire is made into a single layer, tightly wound solenoid and connected to the same battery as before. Write a symbolic equation for the magnetic field of the solenoid and calculate its value.

You and your younger brother are designing an air rifle that will shoot a lead pellet with mass

m = 1.20 g

and cross-sectional area

A = 0.0350 cm².

The rifle works by allowing high-pressure air to expand, propelling the pellet down the rifle barrel. Because this process happens very quickly, no appreciable thermal conduction occurs and the expansion is essentially adiabatic. Your design is such that, once the pressure begins pushing on the pellet, it moves a distance of

L = 60.0 cm

before leaving the open end of the rifle at your desired speed of

v = 100 m/s.

Your design also includes a chamber of volume

V = 10.0 cm³

in which the high-pressure air is stored until it is released. Your brother reminds you that you need to purchase a pump to pressurize the chamber. To determine what kind of pump to buy, you need to find what the pressure of the air must be in the chamber (in Pa) to achieve your desired muzzle speed. Ignore the effects of the air in front of the bullet and friction with the inside walls of the barrel. (Assume that air is diatomic.)

A dielectric-filled parallel-plate capacitor has plate area A = 10.0 cm2 , plate separation d = 6.00 mm and dielectric constant k = 4.00. The capacitor is connected to a battery that creates a constant voltage V = 15.0 V . Throughout the problem, use ϵ0 = 8.85×10−12 C2/N⋅m2 .

a) Find the energy U1 of the dielectric-filled capacitor. Express your answer numerically in joules.

b) The dielectric plate is now slowly pulled out of the capacitor, which remains connected to the battery. Find the energy U2 of the capacitor at the moment when the capacitor is half-filled with the dielectric. Express your answer numerically in joules.

c) The capacitor is now disconnected from the battery, and the dielectric plate is slowly removed the rest of the way out of the capacitor. Find the new energy of the capacitor, U3. Express your answer numerically in joules.

d) In the process of removing the remaining portion of the dielectric from the disconnected capacitor, how much work W is done by the external agent acting on the dielectric? Express your answer numerically in joules.

1. For which of the following reactions is delta S° > 0.

Choose all that apply.

i. C₂H₂(g) + 4H₂O(g)  2CO₂(g) + 5H₂(g)

ii. S(s,rhombic) + 2CO(g)  SO₂(g) + 2C(s,graphite)

iii. 4NH₃(g) + 5O₂(g)  4NO(g) + 6H₂O(g)

iv. NH₄Cl(s)  NH₃(g) + HCl(g)

v. N₂(g) + 2O₂(g)  2NO₂(g)

2. Which of the following transformations represent an increase in the entropy of the system.

Choose all that apply

i. 26 g Hg (liquid, 630K)26 g Hg (gas, 630K)

ii. 26 g Hg (liquid, 618K)26 g Hg (liquid, 246K)

iii. 1 mol Ne (0.672 atm, 497K)1 mol Ne (0.672 atm, 248K)

iv. 3 mol He (9.70 L, 198K)3 mol He (19.4 L, 198K)

v. 44 g Cr (solid, 2.130×10³K)44 g Cr (liquid, 2.130×10³K)