Question

part 2: classify each of the following as elements (e), compounds (c) or mixtures (m). write the letter x if it is none of these.
diamond (c)
air
krypton (k)
water (h₂o)
ammonia (nh₃)
wood
dry ice (co₂)
baking soda (nahco₃)
bronze
salt (nacl)
alcohol (ch₃oh)
bismuth (bi)
sulfuric acid (h₂so₄)
sugar (c₆h₁₂o₆)
milk
gasoline
uranium (u)
pail of garbage
energy
ink
titanium (ti)
iron (fe)
electricity
popcorn
a dog
gold (au)
pizza
concrete

Explanation:

Step1: Recall definitions

• Element: A pure substance made of only one kind of atom.
• Compound: A pure substance formed when two or more elements chemically combine.
• Mixture: A combination of two or more substances that are not chemically combined.

Step2: Analyze each substance

• Diamond (C): Made of only carbon atoms. So, it is an element (E).
• Air: A combination of nitrogen, oxygen, carbon - dioxide etc. So, it is a mixture (M).
• Krypton (K): Made of only krypton atoms. So, it is an element (E).
• Water (H₂O): Formed by chemical combination of hydrogen and oxygen. So, it is a compound (C).
• Ammonia (NH₃): Formed by chemical combination of nitrogen and hydrogen. So, it is a compound (C).
• Wood: A mixture of cellulose, lignin etc. So, it is a mixture (M).
• Dry Ice (CO₂): Formed by chemical combination of carbon and oxygen. So, it is a compound (C).
• Sugar (C₆H₁₂O₆): Formed by chemical combination of carbon, hydrogen and oxygen. So, it is a compound (C).
• Sulfuric Acid (H₂SO₄): Formed by chemical combination of hydrogen, sulfur and oxygen. So, it is a compound (C).
• Bismuth (Bi): Made of only bismuth atoms. So, it is an element (E).
• Alcohol (CH₃OH): Formed by chemical combination of carbon, hydrogen and oxygen. So, it is a compound (C).
• Salt (NaCl): Formed by chemical combination of sodium and chlorine. So, it is a compound (C).
• Bronze: An alloy (mixture) of copper and tin. So, it is a mixture (M).
• Baking Soda (NaHCO₃): Formed by chemical combination of sodium, hydrogen, carbon and oxygen. So, it is a compound (C).
• Titanium (Ti): Made of only titanium atoms. So, it is an element (E).
• Milk: A mixture of water, fats, proteins etc. So, it is a mixture (M).
• Gasoline: A mixture of hydrocarbons. So, it is a mixture (M).
• Uranium (U): Made of only uranium atoms. So, it is an element (E).
• Pail of Garbage: A mixture of various waste materials. So, it is a mixture (M).
• Energy: Not a matter (substance). So, it is X.
• Ink: A mixture of dyes and solvents. So, it is a mixture (M).
• Iron (Fe): Made of only iron atoms. So, it is an element (E).
• Electricity: Not a matter (substance). So, it is X.
• Popcorn: A mixture of corn kernels, seasonings etc. So, it is a mixture (M).
• A dog: A living organism (complex mixture of various compounds and elements). So, it is a mixture (M).
• Gold (Au): Made of only gold atoms. So, it is an element (E).
• Pizza: A mixture of dough, cheese, vegetables etc. So, it is a mixture (M).
• Concrete: A mixture of cement, sand, gravel etc. So, it is a mixture (M).

Answer:

Diamond (C) - E, Air - M, Krypton (K) - E, Water (H₂O) - C, Ammonia (NH₃) - C, Wood - M, Dry Ice (CO₂) - C, Sugar (C₆H₁₂O₆) - C, Sulfuric Acid (H₂SO₄) - C, Bismuth (Bi) - E, Alcohol (CH₃OH) - C, Salt (NaCl) - C, Bronze - M, Baking Soda (NaHCO₃) - C, Titanium (Ti) - E, Milk - M, Gasoline - M, Uranium (U) - E, Pail of Garbage - M, Energy - X, Ink - M, Iron (Fe) - E, Electricity - X, Popcorn - M, A dog - M, Gold (Au) - E, Pizza - M, Concrete - M.