Midterm Exam Review 8th Grade 2018-2019

A balanced chemical reaction obeys the law of

• ideal gases

• definite proportions

• conservation of matter

• conservation of energy

Students use a balance to determine the mass of a marble is 7.5 grams. A graduated bottle contains 10.0 milliliters of water. When the marble is carefully lowered into the graduated bottle and is completely covered with water the volume of the water containing the marble has increased to 12.5 milliliters. Find the density of the marble.

• 0.3 g/ml

• 3.0 g/ml

• 7.5 g/ml

• 12.5 g/ml

On Halloween, you take a glow stick, crack the capsule inside and shake it until it glows. This is an example of light energy being created from ___________________ energy.

• chemical

• mechanical

• solution

• thermal

According to the pH chart, which is the strongest base?

• HCl

• NaOH

• blood

• saliva

Why might a scientist repeat an experiment if she did not make a mistake in the first one?

• Scientists who repeat experiments make the most money.

• It helps ensure the results are consistent and repeatable.

• Repeating ensures the expected results match the hypothesis.

• It helps find portions that can be skipped with the same results.

Why might a scientist repeat an experiment if he/she did not make a mistake in the first one? An experiment should be repeated to

• increase income for increased work.

• prove how interesting the study was.

• ensure the results are accurate.

• eliminate steps and save time.

Beryllium has a nucleus composed of protons and neutrons. Given the data, how many neutrons are in a typical Beryllium nucleus?

• 3

• 4

• 5

• 9

Which statement is accurate for these two subatomic particles: protons and neutrons

• They both have a neutral charge.

• They both have a positive charge.

• They are both located in the nucleus.

• They are both located outside the nucleus.

Describe the structure of an atom.

• The nucleus is the dense center of the atom composed of protons and neutrons. Surrounding the nucleus is an electron cloud composed of electrons.

• The nucleus is the dense center of the atom composed of electrons and neutrons. Surrounding the nucleus is an electron cloud composed of protons.

• The electron cloud is the dense center of the atom composed of electrons. Surrounding the electron cloud is a nucleus composed of protons and neutrons.

• The electron cloud is the dense center of the atom composed of protons and neutrons. Surrounding the electron cloud is a nucleus composed of electrons.

Lemon Juice

Tums (antacid)

Water

Put all of the above household items in order from lowest to highest pH.

• Lemon juice, water, Tums

• Water, Tums, Lemon Juice

• Water, Lemon Juice, Tums

• Tums, water, lemon juice