Chemistry final review

The diagram below shows two forms of lithium, labeled I and II. How are I and II different?

• They have different numbers of neutrons and so exist as isotopes

• They have the same number of protons but different reactivities

• They have different numbers of electrons and thus have different charges

• They exist as ions with different oxidation states

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NGSS.MS-PS1-1

Which is the correct ground state electron configuration for Sodium?

• 1s2s1

• 1s2s22p63s1

• 1s2s22p53s1

• 1s2s22p6

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NGSS.HS-PS1-1

Which occurs as an electron moves from n=2 to n=5 in the hydrogen atom?

• Energy is released

• Energy is transferred to the neutrons

• Energy is absorbed

• Energy is transferred to the protons

At the end of 42 days, 2.00g of phosphorus-32 has decayed to 0.250g. Which represents the half-life of phosphorus-32?

• 8.48 days

• 21.5 days

• 14.3 days

• 10.8 days

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NGSS.HS-PS1-8

The table below provides physical characteristics of certain unidentified substances. Which correctly matches a physical property of a substance and bond strength?

• Substance 1 has a high boiling point due to strong bonds

• Substance 3 has a high melting point due to weak bonds

• Substance 4 has a low density due to weak bonds

• Substance 2 has poor electrical conductivity due to strong bonds

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NGSS.HS-PS1-4

The chart shows relative lengths and energies of different chemical bonds. Which bond is most likely a triple bond?

• 3

• 2

• 4

• 1

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NGSS.HS-PS1-4

An engineer travels to another planet in search of new elements for the space construction trade. He finds a blue/gray, shiny, malleable substance that he names triton. He tests the new element, and it reacts with oxygen and chlorine but not with sodium or calcium. What is the best classification of this new element?

• alloy

• ion

• nonmetal

• metal

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NGSS.HS-PS1-1

NGSS.HS-PS1-2

In a chemistry lab, Jacob heated 15% hydrogen peroxide solution, which decomposes into water and oxygen. The reaction was slow, so he added a small amount of manganese dioxide. The reaction then took place more rapidly. Why was manganese dioxide added to the reaction?

• to act as a catalyst in the reaction

• to lower the reaction temperature

• to act as a product of the reaction

• to act as a reactant in the reaction

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NGSS.HS-PS1-5

Ammonia is manufactured industrially using the Haber process with the reaction shown. N₂(g) + 3H₂(g) ⇌ 2NH₃(g) ΔH=-92.2 kJ Which action would result in a decrease in ammonia produced?

• removing heat

• raising pressure

• removing hydrogen

• adding hydrogen

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NGSS.HS-PS1-5

John wanted to set up an acid-base titration experiment in his lab using dilute hydrochloric acid (HCl) whose hydrogen ion concentration [H⁺] is 1.6x10⁻⁵ M. What is the pH of the HCl?

• pH = 4.8

• pH = 5.8

• pH = -5.8

• pH = -4.8