Homogeneous vs Heterogeneous Mixtures & Pure Substances vs Mixtures

What is a mixture?

A combination of two or more substances that are not chemically combined For example, air is a mixture of gases (nitrogen gas, oxygen gas, carbon dioxide gas) none of which are bonded together (except in the compound carbon dioxide)

What is a pure substance?

An element or compound (two elements bonded together as one molecule) A pure substance is the same composition all the way throughout, and has no variation. For example, water is a pure substance, because the entire substance is only H2O (2 Hydrogen, and 1 Oxygen) The number of each element can NOT change, or you will have a different substance.

Homogeneous or Heterogeneous Mixture?: Beach sand

Heterogeneous (Beach and is made up of different types of rock, as well as pieces of shells. The amount of sand and shells is not the same in every place you look on the beach)

Homogeneous or Heterogeneous Mixture?: Air with smog

Heterogeneous (The amount of smog can vary depending on where you are in the mixture of air)

Homogeneous or Heterogeneous Mixture?: Soil

Heterogeneous (The mixture has varying amounts of each part (humus, dirt, bacteria, rock))

Homogeneous or Heterogeneous Mixture?: Italian salad dressing

Heterogeneous (The mixture is not perfectly uniform, and the amount of one part can vary throughout the dressing. If you leave the dressing long enough, the individual parts will separate out)

Homogeneous or Heterogeneous Mixture?: Chocolate Chip Ice Cream

Heterogeneous (The mixture is not perfectly uniform all the way through. The number of chocolate chips in any area of the ice cream can vary)

Homogeneous or Heterogeneous Mixture?: Carbonated soft drink (w/ bubbles)

Heterogeneous (The mixture is not uniform all the way through. The bubbles (CO2), and the liquid (sugar and water) are not present in equal amounts, and can vary. Once the can is opened, bubbles begin to leave the drink, and CO2 is leaving the mixture)

Homogeneous or Heterogeneous Mixture?: Black coffee

Homogeneous (The amount of coffee per amount of water is the same throughout. Any time something is DISSOLVED in something else, the amount of solvent (the thing dissolved in it) to solute (the liquid it's dissolved in) is the even throughout)

Homogeneous or Heterogeneous Mixture?: Aluminum foil

Homogeneous (The foil's structure is the same throughout the whole thing. The amount of aluminum is the same everywhere you look)

Homogeneous or Heterogeneous Mixture?: Rubbing alcohol

Homogeneous (Rubbing alcohol is made up of Carbon and Hydrogen atoms. These atom shave a set structure, which does not change throughout the mixture. Making it uniform throughout)

Homogeneous or Heterogeneous Mixture?: Paint

Homogeneous (The amount of pigment is the same throughout the paint, or else you would see areas where the paint is lighter/darker)

Homogeneous or Heterogeneous Mixture?: Sugar water

Homogenous (The amount of sugar vs water is the same throughout)

Homogeneous or Heterogeneous Mixture?: Corn syrup

Homogenous (The mixture is uniform throughout)

Mixture or Pure Substance?: Air

Mixture (Although air is made up of elements and compounds, they are NOT chemically bound together)

Mixture or Pure Substance?: Coffee

Mixture (Coffee is a mixture of water and dissolved ground coffee. These things are NOT chemically bound together)

Mixture or Pure Substance?: Salt Water

Mixture (Salt is only DISSOLVED in water. They are NOT chemically bound together. You can remove the salt by evaporating the water)

Mixture or Pure Substance?: Soil

Mixture (Soil is a combination of many different things (dirt, rock, bacteria, humus) which is NOT chemically bound together)

Mixture or Pure Substance?: Blood

Mixture (The components of blood are combined, but can be physically separated from one another)

Mixture or Pure Substance?: Eggs

Mixture (The different parts of the egg are composed of different molecules. Together, they form a mixture)

Mixture or Pure Substance?: Cake Batter

Mixture (These components are NOT chemically bound together)

Mixture or Pure Substance?: Table Salt

NaCl (Sodium Chloride) is a Pure Substance (This is a compound: 2 elements chemically bound together)

Mixture or Pure Substance?: Isopropyl alcohol

Pure Substance (This is a compound (C3H8O): 2 elements chemically bonded together)

Mixture or Pure Substance?: Water

Pure Substance (A compound: 2 elements chemically bonded together)

Mixture or Pure Substance?: Carbon Dioxide

Pure Substance (This is a compound: 2 elements chemically bonded together)

Mixture or Pure Substance?: Oxygen

Pure Substance (This is an element)

Mixture or Pure Substance?: Sodium

Pure Substance (This is an element, Na)

What makes a mixture Heterogeneous?

The composition is NOT uniform throughout the mixture (Vegetable soup is a heterogeneous mixture. Any given spoonful of soup will contain varying amounts of the different vegetables and other components of the soup)

What makes a mixture Homogeneous?

The composition is uniform throughout (It has the same amount of each part of the mixture in every area of the substance. For example, if I make a salad, the amount of lettuce in a certain area will be different than the amount of tomatoes. This means it is NOT uniform throughout. Whereas the amount of salt in a mixture of salt and water will be the same everywhere I look in the mixture)