Matter and Mixtures
What is a homogeneous mixture?
A mixture where the components are uniformly distributed, like air or saltwater.
What is the formula for calculating density?
Density = Mass/Volume
Balance: H₂ + O₂ → H₂O
2 H₂ + O₂ → 2 H₂O
What period and group is calcium (Ca) in?
Period 4, Group 2.
What is condensation?
The process where a gas turns into a liquid.
What is the difference between a physical change and a chemical change?
A physical change alters the appearance but not the composition, while a chemical change results in the formation of a new substance.
A rock has a mass of 450 g and a volume of 150 cm³. What is its density?
3 g/cm³
Balance: Na + Cl₂ → NaCl
2 Na + Cl₂ → 2 NaCl
How many valence electrons does carbon (C) have?
4 valance electrons
What happens during boiling?
A liquid turns into a gas at its boiling point.
What is a heterogeneous mixture?
A mixture where the components are not uniformly distributed, like salad or sand in water.
A wooden block has a density of 0.6 g/cm³ and a volume of 200 cm³. What is its mass?
120 g
Balance: N₂ + H₂ → NH₃
N₂ + 3 H₂ → 2 NH₃
Identify an element in Period 2, Group 8.
Neon
What is freezing?
The process in which a liquid turns into a solid.
What is a homozygous mixture?
a mixture where the components are uniformly distributed throughout
A metal cube has a density of 8.9 g/cm³ and a mass of 534 g. What is its volume?
60 cm³
Balance: K + O₂ → K₂O
4 K + O₂ → 2 K₂O
How many electron shells does potassium (K) have?
4 electron shells
What is deposition?
The process in which a gas turns directly into a solid without becoming a liquid.
What is sublimation?
The process in which a solid changes directly into a gas without becoming a liquid, such as dry ice.
A liquid has a volume of 250 mL and a mass of 325 g. What is its density?
1.3 g/mL.
Balance: CH₄ + O₂ → CO₂ + H₂O
CH₄ + 2 O₂ → CO₂ + 2 H₂O
What is the group number of an element with 7 valence electrons?
17 Halogen Group
What is sublimation?
The process in which a solid turns directly into a gas without becoming a liquid.