Chemical or Physical
This type of change occurs when ice melts into liquid water.
Physical change
This type of bond forms when atoms share electrons.
Covalent bond
This type of bond forms between a cation and an anion.
Ionic bond
Convert 250 cm to meters.
2.50 m
The number of particles is found in one mole.
6.022 × 10²³
Rusting iron is this type of change because a new substance forms.
Chemical change
Name the compound CO.
Carbon monoxide
What is the correct formula for magnesium chloride?
MgCl₂
How many significant figures are in 0.00450?
3
What is the molar mass of CO₂?
44.01 g/mol
Density is classified as this type of property because it can be measured without changing composition.
Physical property
Write the formula for sulfur dioxide.
SO₂
Name the compound Na₂SO₄.
Sodium sulfate
Convert 0.750 L to mL.
750 mL
How many moles are in 36.0 g of H₂O?
2.00 mol
Burning gasoline is a chemical change. Give one observation that supports this classification.
Heat released, light produced, flame, gas produced, or new substances formed
Name the compound P₂Cl₅.
Diphosphorus pentachloride
Write the formula for iron (III) oxide.
Fe₂O₃
A sample has mass = 24.0 g and volume = 8.0 mL. Find density.
4.1 atm
Find the percent by mass of oxygen in H₂O.
88.9%
Classify each as chemical or physical: boiling water, silver tarnishing, crushing sugar, digesting food.
Physical, chemical, physical, chemical 15.4 moles
Write the formula for dinitrogen tetrahydride.
N₂H₄
Why does CaCl₂ have two chloride ions for every calcium ion?
Calcium is Ca²⁺ and chloride is Cl⁻, so two chloride ions are needed to balance charge
Convert 3.50 g/cm³ to kg/m³.
3500 kg/m³
A hydrate of magnesium sulfate is heated to remove the water. A 6.42 g sample of the hydrate is heated until only anhydrous MgSO₄ remains. After heating, the mass of MgSO₄ is 3.28 g. Calculate the number of water molecules removed during heating.
(H₂O = 18.02 g/mol; 1 mol = 6.022 × 10²³ molecules)
1.05 × 10²³ water molecules