Please explain what equations + how you get solve for each questions. Thanks.

Item #2
Learning Goal:
To understand the ideal gas law and be able to apply it to a wide variety of situations.
The absolute temperature T, volume V, and pressure p of a gas sample are related by the ideal gas law, which states that
pV=nRT.
Here n is the number of moles in the gas sample and R is a gas constant that applies to all gases. This empirical law describes gases well only if they are sufficiently dilute and at a sufficiently high temperature that they are not on the verge of condensing.
In applying the ideal gas law, p must be the absolute pressure, measured with respect to vacuum and not with respect to atmospheric pressure, and T must be the absolute temperature, measured in kelvins (that is, with respect to absolute zero). If p is in pascals and V is in cubic meters, use R=8.3145J/(mol⋅K). If p is in atmospheres and V is in liters, use R=0.08206L⋅atm/(mol⋅K) instead.

Part A
A gas sample enclosed in a rigid metal container at room temperature (20.0∘C) has an absolute pressure p1. The container is immersed in hot water until it warms to 40.0∘C. What is the new absolute pressure p2?
Express your answer in terms of p1.

Item #3
An open container holds ice of mass 0.505kg at a temperature of -15.0∘C . The mass of the container can be ignored. Heat is supplied to the container at the constant rate of 740J/minute .
The specific heat of ice to is 2100 J/kg⋅K and the heat of fusion for ice is 334×103J/kg.

Part A
How much time tmelts passes before the ice starts to melt?

Part B
From the time when the heating begins, how much time trise does it take before the temperature begins to rise above 0∘C?

Item #4
Assume all temperatures to be exact.
It takes 2.7×106J of heat to bring a quantity of water from 27∘C to a boil.

Part A
What is the mass of water?
Express your answer using two significant figures.

What's the problem?
you have everything you need, simply plug in. reread/read your homework

Dont know what equations to use...

Write down what you have, what's given and what the question is asking.

If you have a reference table, look at what kind of stuff the question is related to and find the equation that works out the best. There may be multiple methods.

#2a
turn temperature into kelvin (add 273)
PV = nRT
P1 = nRT1/V
P2 = nRT2/V
n, R, and V are constant for states 1 and 2, only temperature changes

P2/P1 = T2/T1
P2 = T2/T1*P1 (temperatures in kelvin)

#3a
Q = mCp(T2-T1)
Find out how much Q needs to be transferred to get the temperature change that you need. You are given power (or Q divided by time). Solve for time.

#3b
Same solution.

#4a
Use the specific heat and heat of fusion from part 3. The heat of fusion is the amount of energy it takes to push ice at 0 degrees Celsius to a state of liquid water at 0 degrees Celsius.

You are given total Q, and you know water boils at 100 degrees Celsius. Using Q = mCp(T2-T1) again, find the mass.

What all the other posters have said. You have everythign you need to solve the problems; you may just need to re-read them more carefully.

It is far more likely that the OP is not familiar with the subject material.

He asked me what P, V, and n meant.

To Stolem...I'm not sure if we can help you if you don't understand the fundamentals. :\

Also, this isn't physics

This post was edited by Dontrunaway on Nov 18 2013 09:48pm

Item #4
Assume all temperature to be exact.

It takes 2.7x10^6 J of heat to bring a quantity of water from 27 C to a boil.

Part A
What is the mass of water?
Express your answer using significant figures.

Q = 2.7x10^6 J
27 C to boiling = 100 C
T = 73 C
(2.7x10^6 J) = m(4186 J/kg)(73 C)
(2.7x10^6 J) = m (4186 J/ kg C)(73 C)
m = ?




Item #5
Assume all temperatures to be exact.
Blood can carry excess heat from the interior to the surface of the body, where the heat is transferred to the outside environment.

If 0.210kg of blood at a temperature of 37.0 ∘C flows to the surface and loses 1800J of heat, what is the temperature of the blood when it flows back into the interior? Assume blood has the same specific heat as water.

0.220 kg blood
37.0 C = T1
loses 1500J
Tf = ?

C~ J/ KG C

-1500 J = (0.220kg)(4186 J / KG C) x (Tf - 236.15)
-1500 J = (920.92 J/ C) x (Tf -37.0 C)
-1500 J / 920.92 J/C = Tf = -37.0 C
-1.63 C = Tf - 37.0 C
-6.63 C + 37.0 C
Tf = 35.37 C

i keep getting wrong answers =((

Its taught almost universally in the second of the general 3 course series for physics.

Ideal Gas Law is chemistry or thermodynamics. Maybe thrown into physics if you aren't in a math-related major.

This post was edited by Dontrunaway on Nov 19 2013 08:30pm