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2 years ago

2)A relatively unreactive metal that is yellow colored.

Chemistry

1 answer:

Vlad1618 [11]2 years ago

3 0

I think we're in the same class lol

1. Sodium

2. Gold

3. Helium

4. Sulfur

5. Magnesium

6. Cesium.

7. Silicon

8. fluorine

9. Nickel

10. Magnesium

11. Tungsten

12. hydrogen

13. Calcium

I did my best, here's my answers. Enjoy.

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The average bond energy (enthalpy) for a C=C double bond is 614 kJ/mol and that of a C−C single bond is 348 kJ/mol. Estimate the

AysviL [449]

Answer:

4.42x10⁻¹⁹ J/molecule

Explanation:

At a double bond, there's sigma and a pi bond, and at a single bond, there's only a sigma bond. Thus, if the energy to break both sigma and pi is 614 kJ/mol, and the energy to break only the sigma bond is 348 kJ/mol, the energy to break only the pi bond is:

E = 614 - 348 = 266 kJ/mol

Knowing that 1 kJ = 1000 J, E = 266,000 J/mol

By Avogadro's number, 1 mol = 6.02x10²³ molecules, thus:

E = 266,000 J/mol * 1mol/6.02x10²³ molecules

E = 4.42x10⁻¹⁹ J/molecule

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2 years ago

In the presence of excess oxygen, methane gas burns in a constant-pressure system to yield carbon dioxide and water: CH4 (g) 2O2

Degger [83]

Answer:

The energy released will be -94.56 kJ or -94.6 kJ.

Explanation:

The molar mass of methane is 16g/mol

The given reaction is:

$CH_{4}(g) + 2O_{2} (g) --> CO_{2} (g)+ 2H_{2}O(l)$

the enthalpy of reaction is given as ΔH = -890.0 kJ

This means that when one mole of methane undergoes combustion it gives this much of energy.

Now as given that the amount of methane combusted = 1.70g

The energy released will be:

$=\frac{energy released by one moleXgiven mass}{molarmass} =\frac{-890X1.7}{16}= -94.56 kJ$

7 0

2 years ago

You are trying to make balloon sculptures. You twist the balloons gently, but they keep popping. Besides trimming your nails, ho

Ivan

Use gloves so your nails wont puncture it and because its soft

4 0

2 years ago

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Which type of reaction is Pb(NO3)2 + 2HCl → PbCl2 + 2HNO3?

Ganezh [65]

Answer:- D. Double- replacement reaction

Explanations:- In general, the decomposition reactions looks like:

$AB\rightarrow A+B$

The given reaction looks different than this and so it is not decomposition reaction.

A single-replacement reaction looks like:

$AB+C\rightarrow AC+B$

Our reaction looks different from this so single-replacement is also not correct.

Synthesis reaction looks exactly opposite to decomposition reaction.

$A+B\rightarrow AB$

The given reaction is different than this and so it is not synthesis reaction also.

A double-replacement reaction looks like:

$AB+CD\rightarrow AD+CB$

In this reaction, the ions are exchanged as could be seen in the general reaction. On reaction side,A is with B and C is with D. On product side, A is with D and C is with B.

The same is happening in the given reaction. Nitrate ion is with lead metal on reactant side and chlorine is with hydrogen, On product side, Chlorine is with lead metal and nitrate ion is with hydrogen. So, ion exchange has taken place here and so this is a double-replacement reaction and choice D is correct.

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3 years ago

Metals and nonmetals all lesson explanation for class 8

WINSTONCH [101]

Answer:

Metalloids elements whose properties are intermediate between those of metals and solid nonmetals or semiconductors.

Some examples:

Chemical element.

Boron.

Semiconductor.

Arsenic.

Silicon.

Selenium.

Antimony.

Germanium.

7 0

3 years ago