Final Exam Review: Concepts and Calculations

Elements can be identified with a spectroscope, which is a machine that separates white light into a spectrum of colors. Element identification is possible with this machine because each element has a unique emission spectrum. Which statement BEST explains why there is a unique emission spectrum for each element?

• Light in the visible light spectrum has too little energy to move the electrons of an atom.

• Light in the visible light spectrum only has enough energy to move electrons to a new orbit.

• Light in the visible light spectrum only has enough energy to remove a proton from an atom.

• Light in the visible light spectrum has too much energy to move protons away from the nucleus.

Element identification with a spectroscope is possible because each element has a ​ unique emission ​ (a)   . This is because the electrons in each element follow unique ​ (b)   between ​ (c)   levels which cause the unique ​ (d)   of (e)   .

• spectrum
• transitions
• energy
• emissions
• light

The model shows an electron moving from its excited state to its ground state. What happens when the electron in the excited state at energy level 2 moves to its ground state in energy level 1?

• energy is released by emitting a photon

• energy is released by absorbing an electron

• energy is absorbed by absorbing a photon

• Energy is absorbed by emitting an electron.

A student reads that a gamma ray is more likely to cause damage to living tissue than a radio wave. She believes this claim based on her knowledge of wavelengths and the energies associated with them. Help support this claim by ordering the wavelengths from shortest to longest.

• Gamma

• X-ray

• Ultraviolet

• Visible

• Radio

This chemical reaction represents the reaction of potassium iodide and lead nitrate to form lead iodide and potassium nitrate.  When correctly balanced, the coefficient for lead iodide will be...

Kl + ​ Pb(NO₃)₂ → ​ (a)   Pbl₂ + KNO₃

• 1
• 2
• 3
• 4
• 5
• 6

Predict the products for the following reactants in a single replacement reaction.  Na + MgCl₂ -->

• NaCl + Mg

• NaCl₂ + Mg

• NaMgCl₂

• NaMg₂ + Cl

Which statement BEST supports the conclusion that a chemical reaction occurred after mixing sodium bicarbonate (NaHCO₃) and distilled water (H₂O)

• A change in temperature

• The solution dissolves in the solvent

• bubbles formed from stirring it

• No change in color

The reaction shown below takes place in an aqueous solution.

CH₃I (aq)  +  KOH (aq)  → CH₃OH(aq)  +  KI (aq)

Which of following changes leads to an increase in the rate of formation of CH₃OH(aq)?

• a decrease in the pressure of the system

• an increase in the pressure of the system

• an increase in the concentration of CH₃I(aq)

• a decrease in the concentration of KOH(aq)

A catalyst is most uses for (a)   the ​ (b)   at which the ​ (c)   is ​ (d)   .

• increasing
• rate
• product
• produced

A​ (a)   increases the ​ (b)   of reaction by ​ (c)   the ​ (d)   energy which means ​ (e)   is required to start the reaction.

• catalyst
• rate
• decreasing
• activation
• less energy