Review problem 5.040 for each reaction, identify in order the substance oxidized, the substance reduced, the oxidizing agent, and the reducing agent. (a) cu + 2h2so4 → cuso4 + so2 +2h2o h2so4; cu; cu; h2so4 cu; h2so4; cu; h2so4 cu; h2o; h2o; cu h2so4; cu; h2so4; cu cu; h2so4; h2so4; cu (b) 3so2 + 2hno3 + 2h2o → 3h2so4 + 2no hno3; so2; so2; hno3 so2; h2o; h2o; so2 so2; hno3; hno3; so2 hno3; so2; hno3; so2 so2; hno3; so2; hno3 (c) 5h2so4 + 4zn → 4znso4 + h2s +4h2o h2so4; zn; h2so4; zn zn; h2so4; zn; h2so4 h2so4; zn; zn; h2so4 zn; h2o; h2o; zn zn; h2so4; h2so4; zn (d) i2 + 10hno3 → 2hio3 + 10no2 + 4h2o i2; hno3; hno3; i2 hno3; i2; hno3; i2 hno3; i2; i2; hno3 i2; hno3; h2o; i2 i2; hno3; i2; hno3

A. The correct option is: Cu; H₂SO₄; H₂SO₄; Cu

B. The correct option is: SO₂; HNO₃; HNO₃; SO₂

C. The correct option is: Zn; H₂SO₄; H₂SO₄; Zn

D. The correct option is: I₂; HNO₃; HNO₃; I₂

Explanation:

A chemical reaction that involves the simultaneous transfer of electrons between two chemical species is known as the redox reaction.

In this reaction, a species that gains electrons, thus getting reduced is called the oxidizing agent. Whereas, species that loses electrons, thus getting oxidized is called the reducing agent.

Oxidation refers to an increase in the oxidation state and reduction refers to a decrease in the oxidation state.

A. Cu + 2H₂SO₄ → CuSO₄ + SO₂ +2H₂O

In this reaction, Cu goes from 0 in Cu to +4 oxidation state in CuSO₄ and thus gets oxidized. Whereas, S goes from +6 in H₂SO₄ to +4 oxidation state in SO₂ and thus gets reduced. Therefore, H₂SO₄ is the oxidizing agent and Cu is the reducing agent.

The correct option is: Cu; H₂SO₄; H₂SO₄; Cu

B. 3SO₂ + 2HNO₃ + 2H₂O → 3H₂SO₄ + 2NO

In this reaction, S goes from +4 in SO₂ to +6 oxidation state in H₂SO₄ and thus gets oxidized. Whereas, N goes from +5 in HNO₃ to +2 oxidation state in NO and thus gets reduced. Therefore, HNO₃ is the oxidizing agent and SO₂ is the reducing agent.

The correct option is: SO₂; HNO₃; HNO₃; SO₂

C. 5H₂SO₄ + 4Zn → 4ZnSO₄ + H₂S +4H₂O

In this reaction, Zn goes from 0 in Cu to +2 oxidation state in ZnSO₄ and thus gets oxidized. Whereas, S goes from +6 in H₂SO₄ to -2 oxidation state in H₂S and thus gets reduced. Therefore, H₂SO₄ is the oxidizing agent and Zn is the reducing agent.

The correct option is: Zn; H₂SO₄; H₂SO₄; Zn

D. I₂ + 10HNO₃ → 2HIO₃ + 10NO₂ + 4H₂O

In this reaction, I goes from 0 in I₂ to +5 oxidation state in HIO₃ and thus gets oxidized. Whereas, N goes from +5 in HNO₃ to +4 oxidation state in NO₂ and thus gets reduced. Therefore, HNO₃ is the oxidizing agent and I₂ is the reducing agent.  

The correct option is: I₂; HNO₃; HNO₃; I₂

the answer for sodium is 0.186

the answer for rubidium is 0.251

according to the u.s. department of agriculture, the label of "certified organic" comes with a set of highly regulated standards for environmental stewardship and resource conservation. some of these include maintenance and improvement of soil quality, prevention of ground and surface water contamination, greenhouse gas regulation, encouragement of biodiversity and conservation of water and energy (see references 1). organic practices integrate natural methods such as mulching, plant diversity, native and adapted plants, crop rotation and the introduction of beneficial insects to control pests without synthetic pesticides.

environmental implications of pesticides

synthetic pesticides ensure high crop yields. while effective in achieving this goal, pesticides contaminate soil, air, ground and surface water, as well as the plants and animals that come into contact with these contaminated sources. freshwater and marine organisms are particularly susceptible to pesticides through agricultural runoff. pesticides also reduce soil fertility (necessitating the use of synthetic fertilizers) and can travel far from the original source, contaminating water and air hundreds of miles from the location of application (see references 2).

health implications of organics

although a subject of particular debate, many recent findings show that organic food is healthier than conventionally grown food. according to the usda, an extensive european union-funded study found that organically grown foods contain more beneficial compounds, such as the vitamins and antioxidants needed to combat many diseases (see references 5). organic milk, meat and eggs are regulated to ensure they are free of hormones administered to conventional livestock and poultry.

health implications of pesticides

pesticides affect human health in three ways: through skin contact, inhalation and ingestion. acute and long-term exposure to pesticides can cause serious health problems for farmers who apply them. the majority of other people are affected by drinking contaminated water and eating contaminated marine life (see references 3). pesticides have been linked to neurological disorders, endocrine and reproductive disorders, immune system deficiencies and cancer. according to the world health organization, acute pesticide poisoning (app) is responsible for significant annual mortality, especially in developing nations (see references 4).

other important considerations

not every small farm or business owner can afford the costly certification process required to be considered "certified organic," even if the farm is not using chemicals. "transitional" farms include those that once used chemicals and are now transitioning to organic-only production. in addition, though organic farming methods offer obvious environmental benefit, an organic apple shipped from around the world creates a different set of environmental problems. locally grown food (particularly locally grown, organic food) is key in sustainable food production.