Reference no: EM133436326
Questions
1. How does an acid-base indicator react when placed in an acidic solution?
A. It dissolves.
B. It increases the pH of the solution.
C. It releases hydroxide ions.
D. It changes color.
2. Which of the following explains why elements in column 17 (the halogens) are very reactive?
A. Their atoms contain three energy levels.
B. Their atoms need only one electron to complete their outer energy level.
C. Their atoms have large masses.
D. Their atoms contain the same number of protons as electrons.
3. A scientist dissolved a white powder in water and noted that the resulting solution was acidic. Why should the scientist not infer that the white powder contained hydrogen ions?
A. Acids never contain hydrogen ions.
B. Bases always contain hydrogen ions.
C. Some acids do not contain hydrogen ions.
D. Acids only contain hydroxyl ions.
4. A student uses an indicator to measure the pH of a solution. The indicator shows a pH of 7. What must be true of this solution?
A. The solution contains neither hydronium ions nor hydroxide ions.
B. The solution has equal amounts of hydronium ions and hydroxide ions.
C. The solution is acidic.
D. The solution is basic.
5. How are parentheses used in chemical formulas?
A. They are used to show atoms that are not part of the molecule.
B. They are used to show which atoms are positively charged.
C. They are used to show which atoms are most easily removed.
D. They are used to show how atoms are grouped in the molecule.
6. A student had a sample of pure water, and added an unknown substance to it. The student noticed that the hydroxide ion concentration in the solution increased as the substance was added. What is true about this newly formed solution?
A. It is basic.
B. It is acidic.
C. It is a buffer.
D. It has a pH of 7.
7. Why is water considered a polar molecule?
A. The molecule has no overall charge.
B. The oxygen and hydrogen atoms share electrons equally.
C. The atoms in the molecule have partial charges.
D. The molecule can only attract positive charges.
8. What would you predict about a chemical that has a hydrogen ion concentration of 1 × 10-12 M?
A. It will form salt and water when added to a base.
B. It contains no hydroxide ions.
C. It has high concentration of hydroxide ions.
D. It has a sour taste.
9. Which results from water's formation of hydrogen bonds?
A. Water has surface tension.
B. Hydrogen and oxygen form ionic bonds.
C. Water is a versatile solvent.
D. The specific heat of water is lower than most solids.
10. In an ionic bond, atoms become charged because
A. they equally share the electrons
B. they do not equally share the electrons
C. one atom will gain an electron and another atom will share
D. one atom gains an electron and another atom will lose an electron
11. Ammonia is a compound. Each molecule of ammonia contains one atom of nitrogen (N) and three atoms of hydrogen (H). What is the chemical formula for ammonia?
A. NH
B. N3H
C. NH3
D. 3HN
12. A scientist performs an experiment on an unknown element. She finds that the unknown element forms an ionic bond with beryllium (Be). She concludes that the unknown element must belong in group 2 of the periodic table. State whether or not you think this result supports her conclusion, and why.
A. No. Beryllium is in Group 2 and is unlikely to react with another Group 2 element.
B. No. Group 2 elements are generally unlikely to react at all.
C. Yes. In an ionic bond, elements share an electron, so this is a logical conclusion.
D. Yes. Ionic bonds only form between elements of the same group.
13. Which is a correct method used in a scientific experiment involving acid and base solutions?
A. Using a pH test strip to measure the oxygen content of a solution
B. Adding an indicator to a solution to test its acidity
C. Adjusting the recorded pH measurements to prove the hypothesis
D. Measuring the pH of a test strip by dipping it into an indicator
14. Kat is investigating a compound and sees that it has even stronger hydrogen bonds than water. What can Kat conclude is most likely true about the specific heat of this compound?
A. It is higher than the specific heat of water.
B. It is equal to the specific heat of water.
C. It is slightly lower than the specific heat of water.
D. It is half as much as the specific heat of water.
15. A student tests the acidity of nitric acid (HNO3) by dissolving a sample of HNO3 in a solution of liquid methane. He then uses an electronic tool to measure the solution and determines that it is highly acidic. What is wrong with the student's experiment?
A. He should not have used any kind of tool for measurements.
B. He dissolved his sample in methane instead of water.
C. He should not have dissolved the sample at all.
D. He used liquid methane instead of gaseous methane.
16. Which statement correctly compares barium nitrate (Ba(NO3)2) and scandium nitrate (Sc(NO3)3)?
A. They contain the same number of NO3 groups.
B. They contain the same number of oxygen atoms.
C. They contain the same total number of atoms.
D. They contain the same number of elements.
17. Why would you expect sodium (Na) to react strongly with chlorine (Cl)?
A. They both need to lose one electron.
B. They both need to gain one electron.
C. Sodium needs to lose one electron, and chlorine needs to gain one electron.
D. Sodium needs to gain one electron, and chlorine needs to lose one electron.
18. Which explains why carbon (C) is such a versatile element?
A. It can form four covalent bonds.
B. It can form only ionic bonds.
C. It can form both ionic and covalent bonds.
D. It can form three ionic bonds.