Question

snc2p chemistry

1. classify each of the materials below. in the center column, state whether the material is a pure substance or a mixture. if the material is a pure substance, further classify it as either an element or compound in the right column. similarly, if the material is a mixture, further classify it as homogeneous or heterogeneous in the right column.

material | pure substance or mixture | element, compound, homogeneous, heterogeneous
--- | --- | ---
concrete | |
sugar + pure water (c₁₂h₂₂o₁₁ + h₂o) | |
iron filings (fe) | |
limestone (caco₃) | |
orange juice (w/pulp) | |
pacific ocean | |
air inside a balloon | |
aluminum (al) | |
magnesium (mg) | |
acetylene (c₂h₂) | |
tap water in a glass | |
soil | |
pure water (h₂o) | |
chromium (cr) | |
chex mix | |
salt + pure water (nacl + h₂o) | |
benzene (c₆h₆) | |
muddy water | |
brass (cu mixed with zn) | |
baking soda (nahco₃) | |

Answer:

To solve this, we analyze each material based on the definitions:

• Pure Substance: Made of one type of particle (element or compound).
• Mixture: Made of two or more substances, not chemically bonded.
• Element: Pure substance with one type of atom.
• Compound: Pure substance with two or more bonded atoms.
• Homogeneous Mixture: Uniform composition.
• Heterogeneous Mixture: Non - uniform composition.

1. Concrete

• It has cement, sand, gravel, etc. So it's a Mixture (multiple substances).
• The components are not uniform, so it's a Heterogeneous Mixture.

2. Sugar + Pure Water ($\ce{C_{12}H_{22}O_{11} + H_{2}O}$)

• Sugar dissolves in water, forming a uniform mixture. So it's a Mixture.
• The composition is uniform, so it's a Homogeneous Mixture (solution).

3. Iron Filings ($\ce{Fe}$)

• Iron is made of only $\ce{Fe}$ atoms. So it's a Pure Substance.
• Since it's a single type of atom, it's an Element.

4. Limestone ($\ce{CaCO_{3}}$)

• $\ce{CaCO_{3}}$ has $\ce{Ca}$, $\ce{C}$, $\ce{O}$ atoms bonded. So it's a Pure Substance.
• It's a combination of different atoms, so it's a Compound.

5. Orange Juice (w/pulp)

• It has juice, pulp, etc. So it's a Mixture.
• The pulp is not uniformly distributed, so it's a Heterogeneous Mixture.

6. Pacific Ocean

• It has water, salts, plankton, etc. So it's a Mixture.
• The composition (salts, organisms) is not uniform, so it's a Heterogeneous Mixture (though some parts like salt - water can be homogeneous, overall with organisms it's heterogeneous).

7. Air Inside a Balloon

• Air has $\ce{N_{2}}$, $\ce{O_{2}}$, $\ce{CO_{2}}$, etc. So it's a Mixture.
• The gases are uniformly mixed, so it's a Homogeneous Mixture (gaseous solution).

8. Aluminum ($\ce{Al}$)

• Aluminum is made of only $\ce{Al}$ atoms. So it's a Pure Substance.
• It's a single type of atom, so it's an Element.

9. Magnesium ($\ce{Mg}$)

• Magnesium is made of only $\ce{Mg}$ atoms. So it's a Pure Substance.
• It's a single type of atom, so it's an Element.

10. Acetylene ($\ce{C_{2}H_{2}}$)

• $\ce{C_{2}H_{2}}$ has $\ce{C}$ and $\ce{H}$ atoms bonded. So it's a Pure Substance.
• It's a combination of different atoms, so it's a Compound.

11. Tap Water in a Glass

• Tap water has water, minerals, etc. So it's a Mixture.
• The minerals are dissolved uniformly, so it's a Homogeneous Mixture (solution, though not pure $\ce{H_{2}O}$).

12. Soil

• Soil has sand, clay, organic matter, etc. So it's a Mixture.
• The components are not uniform, so it's a Heterogeneous Mixture.

13. Pure Water ($\ce{H_{2}O}$)

• $\ce{H_{2}O}$ has $\ce{H}$ and $\ce{O}$ atoms bonded. So it's a Pure Substance.
• It's a combination of different atoms, so it's a Compound.

14. Chromium ($\ce{Cr}$)

• Chromium is made of only $\ce{Cr}$ atoms. So it's a Pure Substance.
• It's a single type of atom, so it's an Element.

15. Chex Mix

• It has different cereals, snacks, etc. So it's a Mixture.
• The components are not uniform, so it's a Heterogeneous Mixture.

16. Salt + Pure Water ($\ce{NaCl + H_{2}O}$)

• $\ce{NaCl}$ dissolves in water, forming a uniform mixture. So it's a Mixture.
• The composition is uniform, so it's a Homogeneous Mixture (solution).

17. Benzene ($\ce{C_{6}H_{6}}$)

• $\ce{C_{6}H_{6}}$ has $\ce{C}$ and $\ce{H}$ atoms bonded. So it's a Pure Substance.
• It's a combination of different atoms, so it's a Compound.

18. Muddy Water

• It has water and suspended mud particles. So it's a Mixture.
• The mud particles are not uniformly distributed, so it's a Heterogeneous Mixture.

19. Brass ($\ce{Cu}$ mixed with $\ce{Zn}$)

• Brass is a mixture of $\ce{Cu}$ and $\ce{Zn}$ (alloy, uniform at atomic level). So it's a Mixture.
• The composition is uniform, so it's a Homogeneous Mixture (solid solution).

20. Baking Soda ($\ce{NaHCO_{3}}$)

• $\ce{NaHCO_{3}}$ has $\ce{Na}$, $\ce{H}$, $\ce{C}$, $\ce{O}$ atoms bonded. So it's a Pure Substance.
• It's a combination of different atoms, so it's a Compound.

Final Table (Summarized)

Material	Pure Substance or Mixture	Element, Compound, Homogeneous, Heterogeneous
sugar + pure water ($\ce{C_{12}H_{22}O_{11} + H_{2}O}$)	Mixture	Homogeneous Mixture
iron filings ($\ce{Fe}$)	Pure Substance	Element
limestone ($\ce{CaCO_{3}}$)	Pure Substance	Compound
orange juice (w/pulp)	Mixture	Heterogeneous Mixture
Pacific Ocean	Mixture	Heterogeneous Mixture
air inside a balloon	Mixture	Homogeneous Mixture
aluminum ($\ce{Al}$)	Pure Substance	Element
magnesium ($\ce{Mg}$)	Pure Substance	Element
acetylene ($\ce{C_{2}H_{2}}$)	Pure Substance	Compound
tap water in a glass	Mixture	Homogeneous Mixture
soil	Mixture	Heterogeneous Mixture
pure water ($\ce{H_{2}O}$)	Pure Substance	Compound
chromium ($\ce{Cr}$)	Pure Substance	Element
Chex mix	Mixture	Heterogeneous Mixture
salt + pure water ($\ce{NaCl + H_{2}O}$)	Mixture	Homogeneous Mixture
benzene ($\ce{C_{6}H_{6}}$)	Pure Substance	Compound
muddy water	Mixture	Heterogeneous Mixture
brass ($\ce{Cu}$ mixed with $\ce{Zn}$)	Mixture	Homogeneous Mixture
baking soda ($\ce{NaHCO_{3}}$)	Pure Substance	Compound