CHEM GUIDE

1. 1. A student reads in a newspaper that the soil in his area contains high levels of arsenic. Based on this information, he believes that his fellow high school classmates have this metal present in their bodies. To test his hypothesis, he conducts an investigation of the soil in his schoolyard to see if it is contaminated with arsenic. He tests seven different areas around the school and finds high levels of arsenic in each. He concludes that the students at the school must have high levels of arsenic in their systems as well. Which of these is the best evaluation of his conclusion?

D. His conclusion is flawed because he did not test the students to see if their bodies contained metal arsenic.

2. When a salt containing copper ions is analyzed by a flame test, a green flame is observed. Which of the following statements describes how the electrons produce the green-colored flame?

A. emit energy as they go from a higher energy level to a lower energy level,

3. The element uranium (U) can undergo both nuclear and chemical reactions. In power plants, the nuclear reactions heats water to produce steam from generating electricity. In the chemical reaction, uranium forms compounds that produce colors from glass and pottery making. What is the maior difference between nuclear and chemical reactions?

C. Nuclear reactions oceur in the nucleus of the atom.

4.When aluminum (Al) is placed in hydrochloric acid (HCI) it produces hydrogen gas (H2) and aluminum chloride (AICI3). When the equation is balanced, what is the coefficient of HCI?

D. 6

5.The aluminum (Al) atoms forms a Al' ion. How many electrons does this ion have?

C. 10

6.Zine (Zn) reacts with hydrochloric acid (HCI) to produce zine chloride (ZnC12) and hydrogen gas (H2) according to the balanced equation below. Which of the following actions would decrease the reaction rate?

d. Decrease the concentration of the hydrochlorie acid.

7. A student was asked to determine the activity of four unknown metals, W.X.Y, and Z.

They are given the metals and four nitrate solutions of the unknown metals. The nitrate are shown across the top of the chart. They placed each metal in each compound except where there is a dashed line- as shown in the chart. Based on the data, how should the student list the metals from least to most active

b. X-Y-W-Z

8.Water is depicted by chemists using the formula H2O. Which of the following is a balanced equation for the synthesis of water from molecular oxygen (02) and hydrogen (H2).

d. O2 + 2H2 ➡️ 2H2O

9. Classification of types of reactions is important to understanding how they will work,

Which of the following reactions is an acid-base reaction?

a. HCI + NaOH -> NaCI + H20

10. Cobalt Hydroxide, Co(OH), is a substance used in manufacturing paints and varnishes.

How many total atoms are in one molecule of cobalt hydroxide?

C. 5

Il. Gases can easily be compressed, whereas liguids and solids resist compression. What is

the best explanation for why gases are so easily compressible?

A. There is more space between gas molecules.

12. A student drew the following concept map about matter.A different student was asked to critique the concept map. What would the best critique statement of this concept map?

B. The words "homogeneous" and "heterogeneous" should both he placed under the heading "mixture.

13. On a cold morning, the driver of a car notices that the low tire pressure light is on in his car. After driving to work, he decides that he will put air in his tires after work. In the warm afternoon, the car's owner notices that the low tire air pressure light is not on anymore. Assuming the tire does not have any holes or other defects, what is the best explanation of this phenomenon?

A. In the afternoon, the gas molecules are excited by the heat, which creates larger volume.

14. The periodic table is a visual display of the chemical elements. Mendeleev, the originator of the periodic table, organized these elements in particular .. properties. Which of the following elements will have the most similar chemical properties?

c. Neon-Krypton-Helium

15. To make sweetened ice tea, a student must add sugar to the tea and water mixture. Which one of the following would dissolve the fastest in the student's pitcher of tea?

d. 30°C tea with 10 grams of granulated sugar.

16. Haley was conducting an experiment to determine the amount of energy contained within a candle. She made her own calorimeter using the ... temperature. Her results were then recorded in her investigation log. Below is a diagram of the setup and the data results that she recorded. How many joules (j) of energy were released from the candle during the time it was combusted?

a. 6,300 J

17. Haley replaced the candle with a potato chip, and then repeated the experiment procedure. She recorded measurements as she combusted . the potato chip. In this experiment, what do the measured calories represent?

d. The amount of energy released from the chemical bonds as the potato chip is combusted.

18. A sample of sodium (Na) was observed by a scientist The scientist wrote down the following observations in her investigation log about the sample. Using the investigation log above, which one of the statements are supported?

a. Physical properties observed: melting point of 208°F and 3.3 grams in the sample.

19. The atomic theory states that all matter is made of atoms. These atoms are made of subatomic particles. What evidence do we have that atoms and subatomic particles exist when the human eye cannot see them?

c. Miliken's oil drop experiment that demonstrated the exact charge of the electron.

20. When Rutherford conducted his gold foil experiment, he hypothesized that most of the alpha particles would go straight through the gold atoms. However, he observed that many of the alpha particles came directly back toward the source, and only a few alpha particles went through. What is the best conclusion from his observations?

d. The gold atom must be structured differently than he originally hypothesized.

21. The following is a model of a nucleus. The protons are represented by + signs, the neutrons are represented by o.

b. Boron: atomic mass of 9

22. A student investigated an unknown substance. The following investigation log provides information about this substance. Based on this investigation log, the unknown substance is best classified as which of the following?

b. Metal in group 14 (4A)

23. Covalent compounds are prevalent in nature and are the primary structure of most organisms. Based on the periodic table, which pair of elements would most likely form a covalent bond?

c. carbon (C) and oxygen (0)

24. Which of the following states of matter could exist at the same temperature?

b. Water vapor and liquid mereury

25. Potassium sulfate K,So, is commonly used in fertilizers and other agricultural applications. What is the mass of one mole of potassium sulfate?

C. 174 g/mol

26. A mole is a unit of measurement, which chemists routinely utilize. Which of the following molar measurements has the greatest mass?

b. 2 moles of calcium (Ca)

27. Classification of reactions is important to scientists so they can predict how they will react. Which one of the following reactions is classified as a single replacement reaction?

b. 2 ZnS + O2 ➡️ 2 ZnO + 2S

28. A welder's propane (CHs) torch is powered by a combustion reaction. The reaction is shown below: C,H, + 0, -> CO, + HO

If 4.0 moles of propane are mixed with 15.0 moles of oxygen O, how many moles of water HO will be formed?

b. 12 moles

29. The diagram below shows energy levels of different types of radiation.

700 m

1 cm

Am radio - amateur radio - aircraft communicator - microwave oven - TV remote control - night vision goggles - rainbow 1000m - Uv light from the sun - airport security scanner - PET scan - terrestrial gamma-ray flashes

Which of these statements best describes the type of radiation with the least amount of energy?

c. Low frequency, long wavelength

30. Below is an abbreviated form the Periodic Table. Which choice below lists the elements shown from least reactive to most reactive?

b. K. Rb. Cs b

31. A student wants to investigate the effects of liquid dish detergent on the properties of water. She sets up the following experiment diagrammed below. According to what you know about the properties of water, which of the following most likely predicts the results of the experiment?

a. The surface tension of water in cup #3 will allow for it to remain rounded on the top of the cup.

32. Hydrogen and carbon are two elements which bond together frequently. Which of the following structures correctly shows how carbon and hydrogen bond?

B

33. Stan and Kenya are investigating the properties of gases in the lab. Stan has a balloon filled with helium, and Kenya has a balloon filled with hydrogen. Under which condition do the gases in the two balloons have the same kinetic energy?

c. Same temperature

34. Below is an energy diagram.What statement is best represented by the letter Y in this energy diagram?

b. the amount of energy given off by the chemical reaction

35. There are four states of matter: solid, liquid, gas and plasma. In order for matter to change between the different states it must undergo a phase change. Which of the following phase changes are endothermic?

c. melting and vaporization

36. The equilibrium reaction of ammonium chloride (NH CI) and ammonia (NH,) and hydrochloric acid (HCI) is shown below. Which altercation will shift the reaction to form more reactants?

d. Increase the concentration NH, and HCI

37. A student is conducting an investigation on the hydrogen (H +) and hydroxide (OH -) concentrations in different solutions. The results are recorded in the data table below.What are most likely the contents of solution A?

c. Stomach acid

38. A student is conducting an investigation on the hydrogen (H +) and hydroxide (OH -) concentrations in different solutions. The results are recorded in the data table below.What is the pH of solution D?

d. 10

39. The "bends" is a condition which some deep sea divers can acquire if they come up too fast from deep underwater. This is because the nitrogen N2 gas in their blood expands, forming larger bubbles obstructing blood circulation. If a diver has 0.10 liters (L) of gas in his blood at an initial pressure of 100 atm, but then rises very quickly to a depth where his blood has a new pressure of 50.0 atm of pressure, what will the new volume of gas in the blood be?

c. 0.20 L

40. A student is conducting an experiment on a balloon. He submerged a balloon into ice

water for 10 sec and then recorded the volume .. and then recorded the volume of the balloon and any change in size. The investigational data is in the table below. If the initial pressure inside the balloon in cold water was at 0.5 atm, what will the pressure be inside the balloon in steaming hot water?

b. 0.37 atm