Chemistry Pre test

A student measures the mass of a 1.00 g aluminum rod as 0.99 g. The best estimate of the percent error associated with this measurement is

• 0.01 %

• 0.1%

• 1%

• 10%

The most efficient way to determine whether a reaction is an exothermic chemical reaction is to use -

• an oxygen probe

• a temperature probe

• a pressure probe

• a pH probe

Tags

NGSS.HS-PS1-4

2Al(C₂H₃0₂)₃ + 3BaSO ₄ → Al₂(S0₄)₃ + 3Ba(C₂H₃0₂)_2.

Which type of chemical reaction does this equation represent?

• Synthesis

• Neutralization

• Oxidation - Reduction

• Double Replacement

What is the oxidation number of an oxide ion?

• -1

• +1

• -2

• +2

What is the molarity of a solution with 0.2 moles of potassium permanganate (KMnO2) dissolved in enough water to make a 500.0 mL solution?

• 0.0004 M

• 0.1 M

• 0.4 M

• 100 M

Tags

NGSS.HS-PS1-7

When 92.0 g of ethanol (C₂H₅OH) are vaporized at its boiling point of 78.3°C, it requires 78.6 kJ of energy. What is the approximate molar heat of vaporization of ethanol in kJ/mol?

• 0.854

• 1.17

• 39.3

• 78.3

Tags

NGSS.HS-PS3-4

What is the density of an aqueous solution that has a mass of 10.081 g and 12.5 mL?

• 126 g/mL

• 0.806 g/mL

• 1.24 g/mL

• 0.008 g/mL

Which element has 16 neutrons, 15 protons, and 15 electrons?

• Sulfur (S)

• Phosphorus (P)

• Gallium (Ga)

• Zinc (Zn)

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Al(s) + 3AgNO₃(aq) –-----> Al(NO₃)₃(aq) + 3Ag(s)

This equation represents which type of chemical reaction?

• Single-replacement

• Double-repalcement

• Decomposition

• Synthesis

In the formula for barium chloride, (BaCl₂), barium (Ba) is written first because it is -

• a single atom

• a larger atom

• the positive ion

• the negative ion