Answer:
C
Explanation:
A physical change is one in which no new substance is formed. The moistening of food by saliva is purely a physical change because no new substance is formed in the process.
A chemical change leads to the formation of a new substance. The action of the enzyme converts starch into sugar which means that a new substance is formed. This is a chemical change.
Answer:
Explanation:
The formula for molality is:
There are 0.210 moles of KBr and 0.075 kilograms of pure water.
Substitute the values into the formula.
Divide.
The molality is <u>2.8 moles per kilogram</u>
Answer:
625 mL
Explanation:
From the question given above, the following data were obtained:
Volume of stock solution (V₁) = 250 mL
Molarity of stock solution (M₁) = 5 M
Molarity of diluted solution (M₂) = 2 M
Volume of diluted solution (V₂) =?
The volume of the diluted solution can be obtained by using the dilution formula as illustrated below:
M₁V₁ = M₂V₂
5 × 250 = 2 × V₂
1250 = 2 × V₂
Divide both side by 2
V₂ = 1250 / 2
V₂ = 625 mL
Therefore, the volume of the diluted solution is 625 mL.
The chemical change that involves breaking down substances using electricity is C. Electrolysis.
