Question

1. identify the following as an example of physical change (p) or a chemical change (c).

______a. cutting a piece of cake
______b. water freezing into ice in a freezer
______c. metal rusting
______d. wood rotting

1. identify each of the following as an element (e) or a compound (c).

______a. calcium (ca)
______b. sugar (c₆h₁₂o₆)
______c. chlorine (cl₂)
______d. water (h₂o)

1. identify each of the following as a homogenous mixture (ho) or a heterogeneous mixture (he)

______a. salad
______b. apple juice
______c. soil
______d. milk

Explanation:

• 11a: Cutting a cake changes its shape but not its chemical composition.
• 11b: Freezing water changes its state (liquid to solid) but not its chemical makeup (\(H_2O\) remains \(H_2O\)).
• 11c: Rusting of metal (e.g., iron rusting to iron oxide) involves a chemical reaction and formation of a new substance.
• 11d: Wood rotting is a biological and chemical process where organic matter is decomposed into new substances.
• 12a: Calcium (\(Ca\)) is an element as it consists of only one type of atom.
• 12b: Sugar (\(C_6H_{12}O_6\)) is a compound made of carbon, hydrogen, and oxygen atoms chemically bonded.
• 12c: Chlorine (\(Cl_2\)) is an element (diatomic form of the chlorine atom).
• 12d: Water (\(H_2O\)) is a compound of hydrogen and oxygen.
• 13a: Salad has visible different components (e.g., vegetables, dressings) that are not uniformly distributed.
• 13b: Apple juice (assuming no pulp and well - mixed) has a uniform composition throughout.
• 13c: Soil contains various particles (sand, clay, organic matter) that are not uniformly mixed.
• 13d: Milk (homogenized milk) has a uniform composition at a microscopic level (fat globules are evenly dispersed).

Answer:

11.
a. \(P\)
b. \(P\)
c. \(C\)
d. \(C\)
12.
a. \(E\)
b. \(C\)
c. \(E\)
d. \(C\)
13.
a. \(He\)
b. \(Ho\)
c. \(He\)
d. \(Ho\)