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3 years ago

which of these stars is least likely to be categorized as a supergiant? A. Betelgeuse B. Pollux C. Sirius A D. Sun Reset Submit

Chemistry

1 answer:

Vesna [10]3 years ago

5 0

Answer: The correct answer is option D.

Explanation: Super-giant stars are the stars which are greater than Sun. They have a mass hundred time greater than Sun and can be thousand times greater than Sun.

The masses of the stars are represented in Solar masses which is the mass of the Sun.

Mass of Betelgeuse = 20 Solar masses

Mass of Pollux = 1.7 Solar masses

Mass of Sirius = 2.02 Solar masses

Mass of Sun = 1 Solar mass.

As, the mass of Sun is the least from the given stars. Hence, it is least considered as a super-giant.

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Main ingredients of plastic bags and natural resources used please

DanielleElmas [232]

polyethylene or polythene are the main ingredients

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3 years ago

A particular reaction, A- products, has a rate that slows down as the reaction proceeds. The half-life of the reaction is found

Thepotemich [5.8K]

Explanation:

Half life of zero order and second order depends on the initial concentration. But as the given reaction slows down as the reaction proceeds, therefore, it must be second order reaction. This is because rate of reaction does not depend upon the initial concentration of the reactant.

a. As it is a second order reaction, therefore, doubling reactant concentration, will increase the rate of reaction 4 times. Therefore, the statement a is wrong.

b. Expression for second order reaction is as follows:

$\frac{1}{[A]} =\frac{1}{[A]_0} +kt$

the above equation can be written in the form of Y = mx + C

so, the plot between 1/[A] and t is linear. So the statement b is true.

Expression for half life is as follows:

$t_{1/2}=\frac{1}{k[A]_0}$

As half-life is inversely proportional to initial concentration, therefore, increase in concentration will decrease the half life. Therefore statement c is wrong.

Plot between A and t is exponential, therefore there is no constant slope. Therefore, the statement d is wrong

8 0

3 years ago

Suppose that 0.250 mol of methane, CH4(g), is reacted with 0.400 mol of fluorine, F2(g), forming CF4(g) and HF(g) as sole produc

shtirl [24]

300 gallons

Explanation:

7 0

2 years ago

Why is a homogeneous mixture not considered a pure substance? Question 6 options: A pure substance can be separated by physical

krok68 [10]

1. Why is a homogeneous mixture not considered a pure substance?

Answer:

A pure substance can be separated by chemical means, while a mixture can be separated by physical means.

2. What is true if mass is conserved in a reaction?

Answer:

There are equal numbers of atoms on both sides.

3. Methane reacts with oxygen then what are the products?

Answer:

carbon dioxide and water

4. Which one of the following is not a homogeneous mixture?

Answer:

vegetable soup

5. The substance is not uniform in appearance and each part of the mixture contains a combination of different ingredients in different ratios.

Answer:

heterogeneous mixtures

6. If a solution is saturated, which of these is true?

Answer:

More solvent can be dissolved

7. Which of these substances are molecules?

Answer:

All compounds are molecules but not all molecules are compounds. Molecular oxygen (O2) and molecular nitrogen (N2) are not compounds because each is composed of a single element. So correct option is 3 and 4.

8. What makes a solution a homogeneous mixture?

Answer:

It is uniform in composition.

9. When a solute is added to a solution, why does it remain homogeneous?

Answer:

The solute dissolves.

10. The chemical formula of glucose is C6H12O6, so it is classified as a(n)

Answer:

pure substance.

11. How many chlorine (Cl) atoms would be in 4 molecules of salt (4 NaCl)?

Answer:

12. In a solution of salt and water, which component is the solute?

Answer:

Salt

13. These substances are all H2O2, Li , NaCl , O2

Answer:

Pure Substances

14. If you have 5 grams of product after a chemical reaction, how many grams of reactants did you have at the start of the reaction?

Answer:

15. What is the difference between a compound and a mixture?

Answer:

A compound is a pure substance, but a mixture is not.

16. A firework exploding would be an example of a(n) ________.

Answer:

Exothermic reaction

17. If Lavoisier heated 100 grams of powdered mercuric oxide to produce 93 grams of liquid mercury, how much oxygen would be released?

Solution

2HgO ==> 2Hg + O2

Mass of HgO = 100 g

Molar mass of HgO = 216.59 g/mol

Moles = mass/molar mass = 0.46 moles

From balance chemcial equation

HgO : O2

2 = 1

0.46 = (1 × 0.46 ) ÷ 2 = 0.23 moles

mass of O2 = moles× molar mass = 0.23 × 32 = 7.36 g

18. Using the Law of Conservation of Matter, determine the number of grams of iron sulfide (FeS) that will be produced in this reaction.

Solution

12g Fe + 64g S → _____ g FeS

According to Law of Conservation of Matter, The total mass of reactant is equal to total mass of product , so the number of grams of iron sulfide (FeS) that will be produced in this reaction as follow.

12 + 64 = 76 g of FeS

Hope this Help.

3 0

3 years ago

Read 2 more answers

25 °C = ________ K which one 298 0 33 197

Paraphin [41]

Answer:

298

hope this helps

have a good day :)

Explanation: