Answer:
B. Chemical changes produce new substances; physical changes do not.
Explanation:
Physical changes only alter appearances, while chemical changes are interactions that create new chemical formulas.
Answer:
Because if you use pen, your chromatography will separate also the colors of the pen and not just your sample.
Explanation:
The pencil since is carbon as simple element, is solid and is not dissolved in solvents like commonly are used in paper chromatography, it will not interrupt the separation of the compounds in your mixture, otherwise, your results will be confuse because you are not sure if the spots that you observe is due to the ink pen or due to the mixture that you want to separate.
The objects may exchange heat between each other if they are in contact with each other.
The two objects will allow flow of heat between them if they have a difference in temperature from each other.
The heat will flow from higher temperature object to lower temperature object. The will reach a final temperature (common to each other) and then there will be no heat transfer between each other.
Answer:
Tone is the author's attitude towards the topic. We can identify it by looking at the setting, characters, details, and word choices. By doing so, it will help us find meaning in the story or passage and help us feel more connected to the writing.
Answer:
Ok to solve this you will need to use the Ideal Gas Law Formula which is as follows:
PV = nRT
P= pressure
V= volume
n= # of moles
R= Universal Gas Constant (0.0821 L x atm/mol x K)
T= Kelvin temperature
1.Simplify the Ideal Gas Law formula to what you need to solve for:
P = (nRT)/ V
2. List all you components as follows (this makes the process easier):
P = ?
V = 45.4 L
n = 0.625 mol
R = 0.0821 L x atm/ mol x K
T = 249 K
To find the Kelvin temperature K = C + 273
3. Plug in all your components in your set up formula:
P = [(0.625 mol)(0.0821 L x atm/ mol x K)(249 K)] / (45.4 L)
4. Cross out all similar units so the only thing left is atm because you are trying to find pressure.
P = [(0.625)(0.0821atm)(249)] / (45.4)
5. Multiply through and simplify
P = 0.28 atm
B. is the correct answer.
Glad I could help!! If you have any other questions just message me. Hopefully this was helpful.
Explanation:
