Is Evaporation a Physical or Chemical Change?

AI Thread Summary
Evaporation is identified as a physical change, as demonstrated by the evaporation of alcohol from a tabletop. The discussion also clarifies that 1 g of ice, liquid water, and water vapor occupy the same volume despite differences in state. At 80k, oxygen is a liquid while nitrogen is a gas due to their boiling points. Various examples of physical and chemical properties are provided, with specific changes classified accordingly, such as grape juice turning to wine being a chemical change. The thread emphasizes the importance of understanding the distinctions between physical and chemical changes in matter.
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Hello everyone I was wondering if someone can check out my answers thanks!

1. A cotton ball is dipped in alcohol and wiped across a tabletop. Explain what happens to the alcohol molecule deposited on the tabletop. Is this a physical or chemical change? The alcohol molecule evaporates, therefore it is a physical change.

2. Which occupies the greatest volume: 1 g of ice, 1 g of liquid water, 1g of water vapor? they are all the same.

3. Oxygen O2, has a boiling point of 90k and nitrogen N2 has a boiling point of 77k. Which is a liquid and which is a gas at 80k? Oxygen is liquid and nitrogen is gas.

4. State whether each of the following is an example of of a physical or chemical property of matter.
a. graphite conducts electricity. chemical
b. bismuth, Bi, loses its iridescence upon melting. chemical
c. a copper penny is smushed into an embossed souvenir. physical

5. State whether each of the following is an example of of a physical or chemical property of matter.
a. carbon dioxide escapes upon the opening of a soda can. chemical
b. a bronze statue turns green. chemical
c. a silver spoon tarnishes. chemical

6. Classify the following changes as physical or chemical. Even i you are incorrect in your assessment, you should be able to defend why you chose as you did.
a. Grape juice turns to wine. chemical
b. Wood burns to ashes. chemical
c. water begins to boil. physical
d. a broken leg mends itself chemical
e. grass grows chemical
f. infant gains 10 pounds chemical
g. a rock is crushed to powder. physical

7. What is the chemical formula for the compound dihydrogen sulfide? H2S

8. What is the chemical name for a compound with the formula Ba3N2? Barium nitride

9. What is the common name for dioxygen oxide? O2
 
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2. Which occupies the greatest volume: 1 g of ice, 1 g of liquid water, 1g of water vapor?
- They are all the same mass, but are they the same volume?

9. What is the common name for dioxygen oxide? Recheck this one and the next~
a. carbon dioxide escapes upon the opening of a soda can.
 
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
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