Gc Pro Profs Quiz Chapter 7 (Sections 1-3)
- 1.
How many moles of compound are there in 20.0 g of K2Cr2O7 (potassium dichromate)?
- A.
15.0
- B.
11.0
- C.
0.0510
- D.
0.068
Correct Answer
D. 0.068Explanation
To find the number of moles of a compound, we need to divide the given mass of the compound by its molar mass. The molar mass of K2Cr2O7 can be calculated by adding the atomic masses of its constituent elements. The molar mass of K2Cr2O7 is 294.18 g/mol. Dividing 20.0 g by 294.18 g/mol gives us approximately 0.068 moles. Therefore, the correct answer is 0.068.Rate this question:
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- 2.
What is the mass of 5 moles of barium hydride, BaH2?
- A.
700.0g
- B.
696.7g
- C.
256.2g
- D.
550.0g
Correct Answer
B. 696.7gExplanation
The molar mass of barium hydride, BaH2, can be calculated by adding the atomic masses of barium (Ba) and hydrogen (H) in the compound. The atomic mass of Ba is 137.33 g/mol, and the atomic mass of H is 1.01 g/mol. Therefore, the molar mass of BaH2 is (137.33 g/mol) + 2(1.01 g/mol) = 139.35 g/mol. To find the mass of 5 moles of BaH2, we multiply the molar mass by the number of moles: 5 mol x 139.35 g/mol = 696.75 g. Rounding to the nearest tenth, the mass is 696.7g.Rate this question:
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- 3.
The correct chemical formula for Chromium(III) Sulfate is what?
- A.
Cr3SO4
- B.
Cr(SO4)2
- C.
Cr2(SO4)3
- D.
Cr3(SO4)2
Correct Answer
C. Cr2(SO4)3Explanation
The correct chemical formula for Chromium(III) Sulfate is Cr2(SO4)3. This is because the Roman numeral III in parentheses after Chromium indicates that it has a +3 charge. Sulfate (SO4) has a -2 charge. To balance the charges, we need two Chromium ions (Cr3+) to combine with three Sulfate ions (SO4^2-), resulting in the formula Cr2(SO4)3.Rate this question:
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- 4.
In a polyatomic ion, the total sum of the oxidation numbers equals what?
- A.
Always -2
- B.
Always -1
- C.
Always zero
- D.
The charge that is on the ion
Correct Answer
D. The charge that is on the ionExplanation
In a polyatomic ion, the total sum of the oxidation numbers equals the charge that is on the ion. This is because the oxidation number represents the charge that an atom would have if electrons were transferred completely. Therefore, when all the oxidation numbers of the atoms in a polyatomic ion are added together, it will equal the overall charge of the ion.Rate this question:
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- 5.
What is the correct order for the parts of a BINARY compound?
- A.
Cation, anion
- B.
Anion, cation
- C.
Anion, polyatomic ion
- D.
Cation, polyatomic ion
Correct Answer
A. Cation, anionExplanation
In a binary compound, the cation (positively charged ion) is always listed first, followed by the anion (negatively charged ion). This is because the cation is the element that loses electrons and becomes positively charged, while the anion is the element that gains electrons and becomes negatively charged. Therefore, the correct order for the parts of a binary compound is cation, anion.Rate this question:
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- 6.
What is the oxidation number for Oxygen in H2SO4
- A.
+2
- B.
-2
- C.
-8
- D.
+6
Correct Answer
B. -2Explanation
In H2SO4, the oxidation number for hydrogen is +1 and the oxidation number for sulfur is +6. Since the compound is neutral, the sum of the oxidation numbers must be zero. Therefore, the oxidation number for oxygen can be calculated as follows: 2(+1) + x + 4(-2) = 0, where x represents the oxidation number for oxygen. Simplifying this equation gives: 2 + x - 8 = 0. Solving for x, we find that the oxidation number for oxygen is -2.Rate this question:
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- 7.
What is the total net charge of MgO
- A.
Hard to tell
- B.
-1
- C.
+1
- D.
0
Correct Answer
D. 0Explanation
The total net charge of MgO is 0 because MgO is an ionic compound consisting of magnesium (Mg) and oxygen (O). Magnesium has a charge of +2, while oxygen has a charge of -2. In order to balance the charges and form a neutral compound, one Mg ion with a charge of +2 combines with one O ion with a charge of -2, resulting in a total net charge of 0.Rate this question:
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- 8.
What is the oxidation number of Pb in PbCl4 ?
- A.
+4
- B.
+2
- C.
+1
- D.
+8
Correct Answer
A. +4Explanation
The oxidation number of Pb in PbCl4 is +4. This is because chlorine (Cl) has an oxidation number of -1, and there are four chlorine atoms in PbCl4. Since the overall charge of PbCl4 is neutral, the sum of the oxidation numbers must be zero. Therefore, the oxidation number of Pb can be calculated as (+4) + 4(-1) = 0, resulting in Pb having an oxidation number of +4.Rate this question:
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- 9.
What is the chemical formula for Calcium Hydroxide?
- A.
Ca2(OH)
- B.
CaOH
- C.
Ca(OH)3
- D.
Ca(OH)2
Correct Answer
D. Ca(OH)2Explanation
The chemical formula for Calcium Hydroxide is Ca(OH)2. Calcium Hydroxide is composed of one calcium ion (Ca2+) and two hydroxide ions (OH-). The subscript 2 in the formula indicates that there are two hydroxide ions for every calcium ion.Rate this question:
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- 10.
Iron (II) Nitrite has a chemical name of what?
- A.
Fe3(NO2)2
- B.
Fe(NO2)2
- C.
Fe(NO2)3
- D.
Fe2(NO2)
Correct Answer
B. Fe(NO2)2Explanation
The correct answer is Fe(NO2)2. Iron (II) Nitrite is formed by combining the iron (II) cation (Fe2+) with the nitrite anion (NO2-). Since the iron (II) cation has a +2 charge and the nitrite anion has a -1 charge, two nitrite ions are needed to balance the charge, resulting in the chemical formula Fe(NO2)2.Rate this question:
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- 11.
Cyanide is a what with a charge of what?
- A.
CN, with a charge of -2
- B.
CN, with a charge of -1
- C.
CO, with a charge of -2
- D.
CN, with a charge of zero
Correct Answer
B. CN, with a charge of -1Explanation
Cyanide (CN) is a negatively charged ion with a charge of -1. This means that it has gained one electron, giving it an overall negative charge. The charge of -1 indicates that cyanide has one more electron than protons, resulting in a net negative charge.Rate this question:
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- 12.
What is the formula and the charge of the copper (II) ion?
- A.
Co+1
- B.
Cu+3
- C.
Co+2
- D.
Cu+2
Correct Answer
D. Cu+2Explanation
The correct answer is Cu+2. The formula for the copper (II) ion is Cu+2, indicating that it has a charge of +2. This means that copper has lost two electrons, resulting in a positive charge. The Roman numeral II in the name indicates the charge of the ion.Rate this question:
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- 13.
How do you find the molar mass of any compound?
- A.
You use the rules, make the squiggle, and add use the net charge to find the unknown.
- B.
You take one atom of each of the elements in the compound and add their atomic masses (red numbers)
- C.
You use the mole map
- D.
You take the number of atoms of each element in the compound, multiply that number by their average atomic masses (red numbers) and add them together.
Correct Answer
D. You take the number of atoms of each element in the compound, multiply that number by their average atomic masses (red numbers) and add them together.Explanation
To find the molar mass of any compound, you need to determine the number of atoms of each element in the compound. Then, you multiply that number by their average atomic masses (represented by red numbers) and add them together. This calculation allows you to determine the total mass of one mole of the compound, which is its molar mass.Rate this question:
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- 14.
What is the percent composition of H in H2SO4?
- A.
8%
- B.
4%
- C.
2%
- D.
1%
Correct Answer
C. 2%Explanation
The percent composition of a compound is the percentage by mass of each element in the compound. In H2SO4, there are 2 hydrogen atoms out of a total of 7 atoms. To calculate the percent composition of hydrogen, we divide the number of hydrogen atoms by the total number of atoms in the compound and multiply by 100. Therefore, the percent composition of H in H2SO4 is 2%.Rate this question:
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- 15.
What is the mass of .75 moles of C6H12O6 ?
- A.
360.36g
- B.
4.51x10^23
- C.
135.14g
- D.
180.18 g
Correct Answer
C. 135.14gExplanation
The molar mass of C6H12O6 (glucose) is 180.18 g/mol. To find the mass of 0.75 moles of C6H12O6, we can multiply the molar mass by the number of moles: 0.75 mol * 180.18 g/mol = 135.14 g. Therefore, the correct answer is 135.14g.Rate this question:
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- 16.
What is the charge of a bromine ion and what is it called?
- A.
Bromide +1
- B.
Bromide -1
- C.
Bromium, +1
- D.
Bromium, -1
Correct Answer
B. Bromide -1Explanation
A bromine ion has a charge of -1 and is called bromide. This means that bromine has gained one electron, resulting in a negative charge.Rate this question:
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- 17.
What is the charge on a platinum (IV) ion?
- A.
+3
- B.
+6
- C.
+3
- D.
+4
Correct Answer
D. +4Explanation
The charge on a platinum (IV) ion is +4. This is because the Roman numeral IV indicates that the platinum ion has a charge of +4. Roman numerals are commonly used in chemistry to indicate the oxidation state or charge of an ion. In this case, the +4 charge indicates that the platinum ion has lost four electrons and has a positive charge of four.Rate this question:
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- 18.
How many aluminum atoms are there in aluminum sulfate?
- A.
2
- B.
1
- C.
3
- D.
4
Correct Answer
A. 2Explanation
Aluminum sulfate has the chemical formula Al2(SO4)3. This means that there are two aluminum atoms in one molecule of aluminum sulfate. Therefore, the correct answer is 2.Rate this question:
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- 19.
How many Carbon atoms are present in this compound? Ba(C2H3O2)2
- A.
6
- B.
2
- C.
4
- D.
1
Correct Answer
C. 4Explanation
In this compound, Ba(C2H3O2)2, there are two acetate ions (C2H3O2-) present. Each acetate ion contains two carbon atoms. Therefore, the total number of carbon atoms in the compound is 4.Rate this question:
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- 20.
This salt, Ca(NO3)2 contains the cation from
- A.
Nitric acid
- B.
Nitrous acid
- C.
Oxygen
- D.
Calcium
Correct Answer
D. CalciumExplanation
The correct answer is calcium. This is because the chemical formula Ca(NO3)2 indicates that the salt contains the cation, or positively charged ion, of calcium (Ca). The other options, nitric acid, nitrous acid, and oxygen, are not present in the salt's formula.Rate this question:
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- 21.
What is the molar mass equal to?
- A.
Total number of atoms
- B.
Total number of moles
- C.
Formula mass
- D.
The number of molecules
Correct Answer
C. Formula massExplanation
The molar mass is equal to the formula mass. Molar mass is the mass of one mole of a substance, and it is calculated by summing up the atomic masses of all the atoms in the substance's chemical formula. This includes all the atoms present in the formula, regardless of the number of atoms or the type of element. Therefore, the correct answer is formula mass, as it represents the molar mass of a substance.Rate this question:
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- 22.
What physical meaning do oxidation numbers have?
- A.
They signify the bond legnth
- B.
They determine the polarity
- C.
They relate the size if the atom to the ionization energy
- D.
They really have no direct physical meaning
Correct Answer
D. They really have no direct physical meaningExplanation
Oxidation numbers are a concept used in chemistry to track the movement of electrons during a chemical reaction. They indicate the hypothetical charge an atom would have if all the bonds were 100% ionic. However, oxidation numbers do not directly correspond to any physical property, such as bond length, polarity, or size of the atom. Instead, they are a purely theoretical construct that helps chemists understand and predict the behavior of elements in compounds.Rate this question:
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- 23.
What is the percentage of Cl in FeCl3 ?
- A.
65.57%
- B.
21.86%
- C.
43.71%
- D.
43.43%
Correct Answer
A. 65.57%Explanation
The correct answer is 65.57%. This means that in FeCl3, 65.57% of the compound is made up of chlorine (Cl).Rate this question:
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- 24.
What is 6.022X10^23?
- A.
A significant number on the mole map
- B.
Avogadro's number
- C.
The number of molecules/particles per one mole of a compound and or atom
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
The correct answer is "All of the above." This is because 6.022x10^23 is a significant number on the mole map, known as Avogadro's number. It represents the number of molecules or particles per one mole of a compound or atom. Therefore, all the statements mentioned in the answer options are true.Rate this question:
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Feb 21, 2023Quiz Edited by
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Feb 21, 2017Quiz Created by
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