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bulgar [2K]
3 years ago
11

If an athlete runs at a speed of 12.9 km/hour, how long will it take the athlete to run a marathon (about 42.2 km)? Express your

answer in hours using the correct number of significant figures. Do not enter your answer using scientific notation.
Chemistry
1 answer:
jekas [21]3 years ago
7 0

Answer:

Time = 3.27s

Explanation:

Time = Distance / Speed

Time = 42.2 / 12.9 = 3.2713

When you multiply the number of significant figures in the result is the same as the number with the least significant figures.

In this case 42.2 has 3 significant figures and 12.9 also has 3 significant figures, therefore the answer must have 3 significant figures too.

Time = 3.27 s

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For which of the following aqueous solutions would one expect to have the largest van’t Hoff factor (i)? a. 0.050 m NaCl b. 0.50
ira [324]

Answer:

The van't hoff factor of 0.500m K₂SO₄ will be highest.

Explanation:

Van't Hoff factor was introduced for better understanding of colligative property of a solution.

By definition it is the ratio of actual number of particles or ions or associated molecules formed when a solute is dissolved to the number of particles expected from the mass dissolved.

a) For NaCl the van't Hoff factor is 2

b) For K₂SO₄ the van't Hoff factor is 3 [it will dissociate to give three ions one sulfate ion and two potassium ions]

Out of 0.500m and 0.050m K₂SO₄, the van't hoff factor of 0.500m K₂SO₄ will be more.

c) The van't Hoff factor for glucose is one as it is a non electrolyte and will not dissociate.

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3 years ago
How does nuclear energy work?
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4 years ago
Why must every redox reaction involve an oxidizing agent and a reducing agent?
vagabundo [1.1K]

A reduced element (which gains electrons) and an oxidized element are required for redox reactions (gives electrons). It is not a redox reaction if we lack both of them (an element can not receive electrons if no element gives electrons and vice versa).

A reduced half and an oxidized half, which always occur together, make up redox processes. While the oxidized half experiences electron loss and an increase in oxidation number, the reduced half obtains electrons and the oxidation number declines. The mnemonic devices OIL RIG, which stand for "oxidation is loss" and "reduction is gain," are simple ways to memorize this. In a redox process, the total number of electrons stays constant. In the reduction half reaction, another species absorbs those that were released in the oxidation half reaction.

In a redox reaction, two species exchange electrons, and they are given unique names:

  • The ion or molecule that accepts electrons is called the oxidizing agent - by accepting electrons it oxidizes other species.
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Hence, what is oxidized is the reducing agent and what is reduced is the oxidizing agent.

<h3>What is the purpose of oxidizing agents and reducing agents?</h3>

By reducing other compounds and shedding electrons, a reducing agent raises its oxidation state. An oxidizing agent gets electrons by oxidizing other compounds; as a result, its oxidation state lowers.

<h3>What is a redox reaction?</h3>

Oxidation-reduction (or "redox") reactions are chemical processes in which electrons are exchanged between two substances. An oxidation-reduction reaction is any chemical process in which a molecule, atom, or ion alters the number of electrons it has, hence increasing or decreasing its oxidation state.

Learn more about redox reaction:  brainly.com/question/13293425

#SPJ4

4 0
1 year ago
Why it is important for steel to go through a fluid phase as it is being produced
BigorU [14]
T is important to go through a fluid phase as it is being produced because the object must go through heat to be melted and then it should be put into a mold to be formed. Also, it go though heat to keep it from cracking and go to be cooled and harden.

Read more on Brainly.com - brainly.com/question/1882456#readmore
3 0
3 years ago
A substance is tested and has a pH of 1.2. How would you classify it?
djyliett [7]

Answer:

A weak acid

Explanation:

Im not sure if its right. But lets see someone else do it.

6 0
3 years ago
Read 2 more answers
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