Answer:A cup of household bleach changes the color of your favorite T-shirt from purple to pink. - chemical change
Water vapor in your exhaled breath condenses in the air on a cold day.- physical change
Plants use carbon dioxide from the air to make sugar.- chemical change
Butter melts when placed in the Sun- physical change
Explanation:
A chemical change leads to the formation of a new substance and is not easily reversible. A physical change does not lead to the formation of a new substance and is easily reversible. Physical changes include condensation, melting,etc while a chemical change is a chemical reaction.
Answer:
86.3 g of N₂ are in the room
Explanation:
First of all we need the pressure from the N₂ in order to apply the Ideal Gases Law and determine, the moles of gas that are contained in the room.
We apply the mole fraction:
Mole fraction N₂ = N₂ pressure / Total pressure
0.78 . 1 atm = 0.78 atm → N₂ pressure
Room temperature → 20°C → 20°C + 273 = 293K
Let's replace data: 0.78 atm . 95L = n . 0.082 . 293K
(0.78 atm . 95L) /0.082 . 293K = n
3.08 moles = n
Let's convert the moles to mass → 3.08 mol . 28g /1mol = 86.3 g
