Answer: Carbon dioxide is a pure substance.
Explanation: A pure substance is defined when a substance has a single type of molecule. If more than 1 type of molecule is present in a substance, then it is considered as a mixture.
- Soda is basically a mixture of water and carbon dioxide. More than 1 type of molecule is present.
- Gasoline is a mixture of may gases. More than 1 type of molecule is present.
- Salt water contains salt and water molecules, hence it is considered as a mixture.
- Carbon dioxide has only 1 type of molecule which is
molecules. Hence, it is a pure substance.
Answer:
Q = 4.056 J
Explanation:
∴ m = 406.0 mg = 0.406 g
∴ <em>C </em>= 1.85 J/g.K
∴ T1 = 33.5°C ≅ 306.5 K
∴ T2 = 38.9°C = 311.9 K
⇒ ΔT = 311.9 - 306.5 = 5.4 K
⇒ Q = (0.406 g)(1.85 J/gK)(5.4 K)
⇒ Q = 4.056 J
C is the answer because animals and plants need water.
Answer : Carbon tetrachloride, 
will show the greatest freezing point lowering.
Explanation :
For non-electrolyte solution, the formula used for lowering in freezing point is,
where,
= lowering in freezing point
= molal depression constant
m = molality
As per question, the molality is same for all the non-electrolyte solution. So, the lowering in freezing point is depend on the only.
That means the higher the value of , the higher will be the freezing point lowering.
From the given non-electrolyte solutions, the value of of carbon tetrachloride is higher than the other solutions.
Therefore, Carbon tetrachloride, will show the greatest freezing point lowering.
Answer is 0.1565417867........
