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3 years ago

According to Table I, which equation represents a change resulting in the greatest quantity of energy released?

2 answers:

8 0

The answer is 3. The releasing of energy means exothermic reaction. So the ΔH should be negative. And the greatest quantity of energy released means that the greatest number. So according to the table I, the answer is 3.

Leni [432]3 years ago

6 0

Answer:

3. N2(g) +3H2(g)->2NH3(g)

Explanation:

Reactions can be broadly classified as endothermic and exothermic reactions. In the former, energy or heat is absorbed by the reactants and the enthalpy change of the reaction is positive. In the later, heat is released ans the enthalpy change of the reaction is negative.

For the given reactions, the enthalpy change or ΔH values are:

1. 2C(s) + 2H2(g) -> C2H4(g) ΔH = +52.4 kJ

2. 2C(s)+3H2(g) -> C2H6(g) ΔH = -84 kj

3. N2(g) +3H2(g)->2NH3(g) ΔH = -91.8 kJ

4. N2(g)+O2(g) -> 2NO(g) ΔH = +182.6 kJ

Reactions 1 and 4 are endothermic while reactions 2 and 3 are exothermic in which heat is released.

More negative the ΔH value, greater is the amount of heat released.

Thus, reaction 3, represents a change resulting in the greatest quantity of energy released

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Can someone help? I wasn't at school the day we did this and I don't understand.

Anton [14]

1) 2700 kg/l
2) 13.6 kg/l
3) 0.1578 kg
4) 8921.5 kg/m3
5) 1.59 kg/l
6) 1.84 kg/l
7) 0.21965 kg
8) 11331.9 kg/m3
9) 7.9167 kg/l
10) 238.095 cm3

Just divide the masses by volume to find out the density, multiply the volume with density to find out the mass and divide the mass by density to find out the volume.
To turn the result into SI unit (kg/l), divide the g by 1000 and ml by 1000.

7 0

4 years ago

Allena and Charissa were discussing whether Cl2 is an element or a compound. Allena said that it is an element because it has on

kobusy [5.1K]

Answer is: Allena is correct. It is an element because it is only made of chlorine atoms.
A chemical element bonded to an identical chemical element is not a chemical compound since it is made from only one element and not from two different elements. Chlorine is molecule, but not compound.

8 0

4 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

A gas containing 80% CH4 and 20% He is sent through a quart/ diffusion tube (see Figure P8.8) to recover the helium, Twenty perc

elena55 [62]

For a gas containing 80% CH4 and 20% He is sent through a quart diffusion tube, the composition is mathematically given as

%He=12.5%

%CH4=87.5%

<h3>What is the composition of the waste gas if 100 kg moles of gas are processed per minute?</h3>

Generally, the equation for the Material balance is mathematically given as

F=R+W

Therefore

100=0.20*1000+W

W=80kmol/min

In conclusion, waste gas compose

2.0/100*100=50/100*20+%*80

Hence

%He=12.5%

%CH4=87.5%