Question

e) copper reacts with oxygen to form a green compound
f) ability to burn

g) water boils at 212 degrees f.

h) iron is ductile and malleable

i) an iron nail rusts

j) combustion of wood

k) green color of leaves

l) density of water is 1.00 g/ml

m) copper conducts electricity

n)salt is soluble in water

o) honey is viscous

1. classify the following as an element or a compound,

a. aluminum:
a. nacl:
b. co₂:
c. cu:

Explanation:

For part e: Copper reacting with oxygen to form a green compound (copper carbonate or copper hydroxide - carbonate) involves a chemical change as new substances are formed. So the property (ability to undergo this reaction) is chemical.
For part f: Ability to burn (combustion) is a chemical property as it involves a reaction with oxygen to produce new substances.
For part g: Boiling point is a physical property as it describes a state change without altering the substance's chemical identity.
For part h: Ductility and malleability are physical properties related to the physical state/structure of the metal.
For part i: Rusting of iron (formation of iron oxide) is a chemical change, so the property (tendency to rust) is chemical.
For part j: Combustion of wood produces ash, gases etc., new substances, so it's a chemical change (and the ability to combust is a chemical property).
For part k: Color is a physical property as it can be observed without changing the substance's chemical composition.
For part l: Density is a physical property as it's a characteristic of the substance's physical state.
For part m: Electrical conductivity is a physical property as it relates to the movement of electrons in the metal without changing its chemical identity.
For part n: Solubility is a physical property as it's about the ability to dissolve (a physical process, though sometimes related to interactions, but the dissolved substance can be recovered without chemical change in many cases).
For part o: Viscosity is a physical property related to the flow characteristics of the substance.

For question 7:
a. Aluminum: It is an element as it consists of only one type of atom (Al atoms) and is found on the periodic table as a single element.
NaCl: It is a compound as it is made up of sodium (Na⁺) and chloride (Cl⁻) ions, formed by the chemical combination of two different elements (sodium and chlorine) in a fixed ratio.
CO₂: It is a compound as it is composed of carbon and oxygen atoms chemically bonded in a fixed ratio (1:2).
Cu: It is an element as it consists of only copper atoms and is a pure elemental substance.

Answer:

e) Chemical
f) Chemical
g) Physical
h) Physical
i) Chemical
j) Chemical
k) Physical
l) Physical
m) Physical
n) Physical
o) Physical

7.
a. Aluminum: Element
a. NaCl: Compound
b. CO₂: Compound
c. Cu: Element