Moles
What is a mole in chemistry, and what number is used to represent one mole of particles?
A mole is a unit used to count particles.
1 mole = 6.02 × 10²³ particles (Avogadro’s number).
What is the name of the compound for sodium and chlorine?
Sodium chloride
What is the loss of electrons in a chemical reaction
Oxidation
What is a physical property?
This type of property can be observed without changing the substance’s identity.
What are the three main subatomic particles, and what charge does each have?
• Protons have a positive (+) charge
• Neutrons have no charge (0)
• Electrons have a negative (–) charge
How many atoms are in 2 moles of carbon?
2 moles × 6.02 × 10²³ atoms/mol= 1.204 × 10²⁴ atoms of carbon
What is the name of the compound AI2 O3?
Aluminum oxide
What process involves the gain of electrons
Reduction
What is a physical change?
Melting ice into water is an example of this type of change.
What is the difference between a metal, a nonmetal, and a metalloid?
• Metals conduct electricity and heat well and are usually shiny
• Nonmetals do not conduct electricity well
• Metalloids have properties of both metals and nonmetals and are found along the zigzag line on the periodic table
What is the mass of 1.5 moles of sodium (Na)? (Molar mass = 23 g/mol)
1.5 moles × 23 g/mol= 34.5 grams of sodium
The term for the positive ion in an ionic compound.
What is The Cation?
What mnemonic (saying or phrase) helps remember oxidation and reduction
LEO the lion says GER
What is a chemical property?
Flammability and reactivity with oxygen are examples of this type of property.
What is an ion, and how is it formed?
• An ion is an atom that has gained or lost electrons.
• Losing electrons makes a positive ion (cation)
• Gaining electrons makes a negative ion (anion)
How many moles are in 45 grams of calcium carbonate (CaCO₃)?
(Molar mass of CaCO₃ ≈ 100 g/mol)
Moles = mass ÷ molar mass
45 g ÷ 100 g/mol= 0.45 moles of CaCO₃
High melting/boiling points, hard but brittle.
What are Properties of Ionic Compounds?
What substance causes another to be oxidized by accepting electrons
Oxidizing agent
What is a chemical change?
Rust forming on iron is classified as this type of change because a new substance forms.
What is an isotope?
• An isotope is an atom of the same element.
A sample contains 3.01 × 10²³ molecules of oxygen gas (O₂).
What is the mass of the sample in grams?
3.01 × 10²³ molecules ÷ 6.02 × 10²³= 0.5 moles of O₂
What is the formula for ammonium nitrate?
NH4 NO3
What type of reaction involves the simultaneous transfer of electrons between substances
A redox reaction
What is the formation of a new substance?
This is the best evidence that a chemical change has occurred.
Why do isotopes of the same element have the same chemical properties but different masses?
• Isotopes have the same number of protons and electrons, so they behave the same chemically.
They have different numbers of neutrons, which changes their mass.