Chem Midterm

Cd⁺² // Find: Mass #, protons, neutrons

Mass #: 112.411

Protons: 48

Neutrons: 64

⁵³Cr // Find: Mass #, protons, neutrons

Mass #: 53

Protons: 24

Neutrons: 29

As // Find: Mass #, protons, neutrons

Mass #: 74.9216

Protons: 33

Neutrons: 42

What happens to the mass of a sodium atom after the change to become an ion?

The mass of a sodium atom remains essentially unchanged when it becomes a sodium ion.

Is the sodium ion cation or anion?

cation

Why does the sodium ion have a charge of +1 and not -1 or -2?

Loses 1 electron in need to become noble gas

ID 2 other elements with similar chemical properties as sodium

Lithium and potassium

What happens on the atomic level when the temperature of a substance rises?

The atoms increase in speed

What causes atmospheric pressure?

Atmospheric pressure is caused by the weight of air molecules pressing down on the Earth's surface.

How/why does the atmospheric pressure change?

Atmospheric pressure changes due to variations in temperature, altitude, and humidity, which affect the density of air.

Write in Scientific Notation: 200,000

2.0 × 10⁵

1 kg=2.2 lbs. || 5 lbs of Gold = how many grams

2267.96 g

Density of nickel 8.8 g/mL. How many mg is a 2.0 cL piece of nickel

176,000 mg

How many moles of Oxygen will be in a 200g sample?

12.5 moles

How many atoms of Calcium will be in a 200g sample?

3.01 × 10²⁴

How many grams are 2.5×10^-4 ug sample?

2.5 × 10^-10

How many grams are 2.5×10²⁴ atoms of silver?

445.18

How many atoms are in a piece of silver that weighs 2.0kg?

1.12 × 10²⁵

Determine the volume of Nickel in millimeters that contains exactly 2.4×10²⁴ atoms. Density is 9.8 g/mL

23.83

Balance: Al₂(SO₃)₃ + NaOH —> Na₂SO₃ + Al(OH)₃

Balance: NH₄NO₃ —> N₂O + H₂O

Balance: Be₂C + H₂O —> Be(OH)₂ + CH₄

Balance: Al₂O₃ + Fe —> Fe₃O₄ + Al

Identify Type of Compound: Cr(PO₃)₂

Ionic

Identify Type of Compound: PCl₅

Molecule

Identify Type of Compound: V₂O₃

Ionic

Identify Type of Compound: KNO₃

Ionic

Identify Type of Compound: NO

Molecule

Identify Type of Compound: Potassium oxide

Ionic

Identify Type of Compound: Alumnium nitrate

Ionic

Identify Type of Compound: Magnesium hydroxide

Ionic

Identify Type of Compound: Carbon tetraflouride

Molecule

Identify Type of Compound: Butyne

Hydrocarbon

Identify Type of Compound: Diphosphorus pentachloride

Molecule

If a compound has a formula of MO₂ what is the charge of “M”

+4

What is a mixture?

A combination of two or more substances that keep their own properties and can be separated physically.

Element

A pure substance made of only one type of atom that cannot be broken down into simpler substances.

Pure Substance

A material with a uniform and definite composition, consisting of either one element or one compound.