A, b and d if you don't count the tooth.
The life cycle of a tree provides us with a good example of recycling in nature<span>. Leaves fall from trees and form leaf litter on the forest floor. </span>
Pure Substance- Element
Explanation:
Pure Substance VS. Mixture:
A pure Substance CANNOT be separated by physical changes, but a Mixture can.
PURE SUBSTANCE: Element VS. Compound:
An Element is one simple atom while a compound is two or more.
Example: Al (Aluminum) is an Element. CaCl (Calcium Chloride) is a compound.
You can split a compound with chemical changes because if you were to take the example, it would be a Calcium atom and a Chlorine atom.
You CANNOT split a single atom (Element) unless you want to make an atomic bomb which takes a lot of energy and you don’t want to destroy the whole world.
MIXTURE: Homogeneous VS. Heterogeneous:
Homo- mixed; cannot differentiate pieces
Hetero- can differentiate pieces
EX: homo- ketchup (can you see the difference in the vinegar and tomato paste? No)
Hetero- chicken noodle soup (there’s broth, chicken, peas, carrots, and other things)
<span>CH4+2O2———> CO2 +2H2O
M(CH4)=16.0 g/mol
</span>30g CH4*1mol/16.0 g - mol of CH4
30g CH4*(1mol/16.0 g)*(2 mol H2O/1 mol CH4) =15 mol H2O
30g CH4*(1mol/16.0 g)*(2 mol H2O/1 mol CH4)*22.4L/1mol=84 L H2O as gas, but at STP water should be liquid,so
15 mol H2O*18g H2O/1 mol=270g of H2O
270g*1ml/1g= 270 ml =0.27 L of liquid water, in reality it should be like this,
but I do not know what people who created this problem wanted H2O as liquid or as gas
The first choice is correct