Question 1

In which compound does chlorine have an oxidation number of +5?

Accepted Answer

The answer of In which compound does chlorine have an...

Question 2

Magnesium metal burns brightly in the air to make a white powder.What are the likely products?

Accepted Answer

When magnesium burns in air, it combines with oxygen to form magnesium oxide (MgO) and it also reacts with nitrogen in the air to form magnesium nitride (Mg3N2). The products are not likely to contain carbon, sulfur or any other element in the given options, therefore, options A, B, C, and E can be eliminated. The only option that includes MgO and Mg3N2 is option D.

Question 3

Approximately 46.4 grams of sodium acetate (82.0 g/mol)will dissolve in 100 grams of water at 20°C.If 2.75 mol NaCH₃COO is dissolved in 355g H₂O,the solution is __________

Accepted Answer

First, we need to calculate the maximum amount of sodium acetate that can dissolve in 355g of water at 20°C.

Using the given solubility data, we can calculate the maximum amount of sodium acetate that will dissolve in 100g of water:

46.4 g NaCH3COO / 82.0 g/mol = 0.566 mol NaCH3COO

Multiplying this value by the mass of water in the final solution:

0.566 mol/L x 355 g = 201 g NaCH3COO

Therefore, if we dissolve 2.75 mol of NaCH3COO in 355g of water, we have added more solute than the solvent can dissolve at the given temperature. This means that the solution is supersaturated.

Question 4

Potassium is a very reactive metal,but in compounds it is present as the potassium ion and is not very reactive.For example,dry potassium bicarbonate powder can be used to extinguish burning liquids.Why is there such a difference in the reactivity of potassium metal and the potassium ion?

Accepted Answer

The reactivity of potassium metal is due to the presence of one extra electron, which is easily transferable to other substances. On the other hand, in compounds, potassium exists as the potassium ion, which has lost this extra electron and is thus not very reactive.

Question 5

Water-soluble toxic chromium compounds are waste products of electroplating operations,but the chromium can be precipitated as Cr(OH)₃ to remediate the water.How much 1.0 M NaOH solution is needed to remove the chromium from 100 L of a solution that is 0.001 M in Cr³⁺?

Accepted Answer

The answer of Water-soluble toxic chromium compounds are waste products...

Question 6

Nitrogen-fixing bacteria and plants are capable of converting atmospheric nitrogen to ammonia.This process is an example of __________

Accepted Answer

Nitrogen-fixing bacteria and plants convert atmospheric nitrogen (N2) to ammonia (NH3) through a process that involves the transfer of electrons, which is characteristic of an oxidation-reduction (redox) reaction. In this process, atmospheric nitrogen is reduced to ammonia.

Question 7

One type of alcohol breathalyzer used by law enforcement involves the following reaction.The amount of ethanol present is determined by a change in color of the solution.What type of reaction is this? 3 CH₃CH₂OH(g)+ 2 K₂Cr₂O₇(aq)+ 8 H₂SO₄(aq)$\to$ 3 CH₃COOH(aq)+ 2 Cr₂(SO₄)₃(aq)+ 2 K₂SO₄(aq)+ 11 H₂O( )

Accepted Answer

The given reaction involves the oxidation of ethanol to acetic acid by the potassium dichromate(VI) in an acidic medium. The change in color of the solution is due to the reduction of the chromium(VI) ions to chromium(III) ions in the process. This is an example of an oxidation-reduction reaction.

Question 8

Reduction is the __________

Accepted Answer

Reduction in chemistry refers to the gain of electrons by a molecule, atom, or ion.

Question 9

Oxidation refers to __________

Accepted Answer

Oxidation is defined as the process of losing electrons or increasing the oxidation state of an atom, ion, or molecule. This is represented by an increase in the oxidation number of the species.

Question 10

What is the oxidation number of carbon in the bicarbonate ion (HCO₃^-)?

Accepted Answer

In the bicarbonate ion (HCO₃⁻), the oxidation number of hydrogen is +1, and each oxygen is -2. The sum of oxidation numbers in the ion must equal the charge of the ion, which is -1. Therefore, the oxidation number of carbon is +4 to balance the overall charge.

Question 11

Reduction refers to __________

Accepted Answer

Reduction refers to a decrease in oxidation number. This means that an atom or molecule gains electrons, which results in a decrease in its oxidation state.

Question 12

In which of the following does manganese have the highest oxidation number?

Accepted Answer

The answer of In which of the following does manganese...

Question 13

In which one of the following compounds is the oxidation number of S equal to +4?

Accepted Answer

The answer of In which one of the following compounds...

Question 14

Sodium metal easily loses an electron to form the sodium ion.In this process,sodium is __________

Accepted Answer

Sodium is ionized because it loses an electron to form a sodium ion, and it is oxidized because losing an electron is the process of oxidation.

Question 15

Chalk is mostly calcium carbonate.Could chalk dust catch fire and burn in air?

Accepted Answer

The carbon in the carbonate ion is already in its highest oxidation state, meaning it cannot undergo further oxidation and burn. Therefore, chalk dust cannot catch fire and burn in air.

Question 16

What is the oxidation number of P in H₂PO₄^-?

Accepted Answer

The oxidation number of hydrogen is +1, and the oxidation number of oxygen is -2. The overall charge of the ion is -1. Let the oxidation number of P be x. Then, we have:2(+1) + x + 4(-2) = -12 + x - 8 = -1x = +5

Question 17

Oxygen gas reacts with many metals.During this process,oxygen __________

Accepted Answer

The answer of Oxygen gas reacts with many metals.During this...

Question 18

Limestone (CaCO₃,100.1 g/mol)is present in many sedimentary rocks.Suppose the limestone in a 5.000 g rock sample is dissolved in hydrochloric acid,and then 33.30 mL of 0.1500 M Na₂C₂O₄ is added to precipitate the Ca²⁺ ions as CaC₂O₄ (128.1 g/mol).What is the mass percent limestone in the original rock sample?

Accepted Answer

The answer of Limestone (CaCO₃,100.1 g/mol)is present in many sedimentary...

Question 19

Approximately 192 grams of ammonium nitrate (80.0 g/mol)will dissolve in 100 grams of water at 20°C.If 21.0 mol NH₄NO₃ is dissolved in 875 g H₂O,the solution is __________

Accepted Answer

The question provides information about the solubility of ammonium nitrate in water, but it does not provide any information about the solubility of NH₄NO₃ in H₂O. Therefore, we cannot determine whether the solution is unsaturated, supersaturated, or dilute. However, we do know that 875 g of solvent is used, which is greater than the 100 g of water used in the solubility information. Therefore, the solution is saturated, as no more solute can be dissolved in the given amount of solvent.

Question 20

Methane (CH₄)is a suitable fuel for burning because it is readily oxidized by oxygen gas,forming carbon dioxide and water.Hydrogen is also a good fuel for burning with oxygen gas,forming water as a product.What change in oxidation number always accompanies oxidation?

Accepted Answer

Oxidation is defined as a loss of electrons, which results in an increase in oxidation number. Therefore, the change in oxidation number always accompanies oxidation is an increase.

Quiz 8: Aqueous Solutions-Chemistry of the Hydrosphere

In which compound does chlorine have an oxidation number of +5?

Magnesium metal burns brightly in the air to make a white powder.What are the likely products?

Approximately 46.4 grams of sodium acetate (82.0 g/mol) will dissolve in 100 grams of water at 20°C.If 2.75 mol NaCH₃COO is dissolved in 355g H₂O,the solution is __________

Potassium is a very reactive metal,but in compounds it is present as the potassium ion and is not very reactive.For example,dry potassium bicarbonate powder can be used to extinguish burning liquids.Why is there such a difference in the reactivity of potassium metal and the potassium ion?

Water-soluble toxic chromium compounds are waste products of electroplating operations,but the chromium can be precipitated as Cr(OH) ₃ to remediate the water.How much 1.0 M NaOH solution is needed to remove the chromium from 100 L of a solution that is 0.001 M in Cr³⁺?

Nitrogen-fixing bacteria and plants are capable of converting atmospheric nitrogen to ammonia.This process is an example of __________

Reduction is the __________

Oxidation refers to __________

What is the oxidation number of carbon in the bicarbonate ion (HCO₃^-) ?

Reduction refers to __________

In which of the following does manganese have the highest oxidation number?

In which one of the following compounds is the oxidation number of S equal to +4?

Sodium metal easily loses an electron to form the sodium ion.In this process,sodium is __________

Chalk is mostly calcium carbonate.Could chalk dust catch fire and burn in air?

What is the oxidation number of P in H₂PO₄^-?

Oxygen gas reacts with many metals.During this process,oxygen __________

Approximately 192 grams of ammonium nitrate (80.0 g/mol) will dissolve in 100 grams of water at 20°C.If 21.0 mol NH₄NO₃ is dissolved in 875 g H₂O,the solution is __________

Methane (CH₄) is a suitable fuel for burning because it is readily oxidized by oxygen gas,forming carbon dioxide and water.Hydrogen is also a good fuel for burning with oxygen gas,forming water as a product.What change in oxidation number always accompanies oxidation?

Quiz 8: Aqueous Solutions-Chemistry of the Hydrosphere

In which compound does chlorine have an oxidation number of +5?

Magnesium metal burns brightly in the air to make a white powder.What are the likely products?

Approximately 46.4 grams of sodium acetate (82.0 g/mol) will dissolve in 100 grams of water at 20°C.If 2.75 mol NaCH3COO is dissolved in 355g H2O,the solution is __________

Potassium is a very reactive metal,but in compounds it is present as the potassium ion and is not very reactive.For example,dry potassium bicarbonate powder can be used to extinguish burning liquids.Why is there such a difference in the reactivity of potassium metal and the potassium ion?

Water-soluble toxic chromium compounds are waste products of electroplating operations,but the chromium can be precipitated as Cr(OH) 3 to remediate the water.How much 1.0 M NaOH solution is needed to remove the chromium from 100 L of a solution that is 0.001 M in Cr3+?

Nitrogen-fixing bacteria and plants are capable of converting atmospheric nitrogen to ammonia.This process is an example of __________

Reduction is the __________

Oxidation refers to __________

What is the oxidation number of carbon in the bicarbonate ion (HCO3-) ?

Reduction refers to __________

In which of the following does manganese have the highest oxidation number?

In which one of the following compounds is the oxidation number of S equal to +4?

Sodium metal easily loses an electron to form the sodium ion.In this process,sodium is __________

Chalk is mostly calcium carbonate.Could chalk dust catch fire and burn in air?

What is the oxidation number of P in H2PO4-?

Oxygen gas reacts with many metals.During this process,oxygen __________

Approximately 192 grams of ammonium nitrate (80.0 g/mol) will dissolve in 100 grams of water at 20°C.If 21.0 mol NH4NO3 is dissolved in 875 g H2O,the solution is __________

Methane (CH4) is a suitable fuel for burning because it is readily oxidized by oxygen gas,forming carbon dioxide and water.Hydrogen is also a good fuel for burning with oxygen gas,forming water as a product.What change in oxidation number always accompanies oxidation?

Approximately 46.4 grams of sodium acetate (82.0 g/mol) will dissolve in 100 grams of water at 20°C.If 2.75 mol NaCH₃COO is dissolved in 355g H₂O,the solution is __________

Water-soluble toxic chromium compounds are waste products of electroplating operations,but the chromium can be precipitated as Cr(OH) ₃ to remediate the water.How much 1.0 M NaOH solution is needed to remove the chromium from 100 L of a solution that is 0.001 M in Cr³⁺?

What is the oxidation number of carbon in the bicarbonate ion (HCO₃^-) ?

What is the oxidation number of P in H₂PO₄^-?

Approximately 192 grams of ammonium nitrate (80.0 g/mol) will dissolve in 100 grams of water at 20°C.If 21.0 mol NH₄NO₃ is dissolved in 875 g H₂O,the solution is __________

Methane (CH₄) is a suitable fuel for burning because it is readily oxidized by oxygen gas,forming carbon dioxide and water.Hydrogen is also a good fuel for burning with oxygen gas,forming water as a product.What change in oxidation number always accompanies oxidation?