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3 years ago

All elements have a ΔHf of ___kJ/mole at standard temperature and pressure.

1 answer:

7 0

Answer is: 0 (zero).
ΔHf is the standard enthalpy or heat of formation of the compound. Standard enthalpy is the change of enthalpy during the formation of one mole of the substance from elements. All elements in their standard states have a standard enthalpy of formation of zero,so there is no change involved in their formation.

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5) answer is A

Burka [1]

Answer:

A) positive; added

Explanation:

Based on the reaction:

2NaHCO3(s) + 129kJ → Na2CO3(s) + H2(g) + CO2(g)

2 moles of NaHCO3 requires 129kJ to produce 1 mole of Na2CO3, 1 mole of H2 and 1 mole of CO2.

That means, the energy must be added being, thus, an exothermic reaction. The exothermic reactions have ΔH >0.

Thus, right answer is:

A) positive; added

3 0

3 years ago

Methanol and butanol are alcohols. Alcohols have the same_______________ as alkanes and the __________ identifies the compound a

Margarita [4]

Answer:

Methanol and butanol are alcohols. Alcohols have the same_______________ as alkanes and the __________ identifies the compound as an alcohol.

Explanation:

Alcohols belong to a group of organic compounds which contain -OH group as the functional group.

So alcohols have the same carbon -hydrogen bonds as alkanes and the -OH functional group identifies the compound as an alcohol.

8 0

3 years ago

Balance this chemical equation with an explanation please: CH3CH2OH + O2 = CO2 + H2O

STALIN [3.7K]

CH3CH2OH + 3O2 = 2CO2 + 3H2O

Basically you do trial and error on both sides so they can be equal

3 0

3 years ago

Enter the balanced NET IONIC equation for the potentially unbalanced equation AgNO3(aq)+NaCl(aq)→AgCl(s)+NaNO3(aq).

Zigmanuir [339]

Answer:

$Ag^+(aq)+Cl^-(aq)\rightarrow AgCl(s)$

Explanation:

Hello!

In this case, since the net ionic equations are ionic representations of the molecular equation in which the spectator ions (those at both reactants and products sides) are cancelled out, we first write the complete ionic equation for this reaction, considering that the solid silver chloride is not ionized due to its precipitation:

$Ag^+(aq)+NO_3^-(aq)+Na^+(aq)+Cl^-(aq)\rightarrow AgCl(s)+Na^+(aq)+NO_3^-(aq)$

Whereas the nitrate and sodium ions are cancelled out for the aforementioned reason as they are the spectator ions, to obtain:

$Ag^+(aq)+Cl^-(aq)\rightarrow AgCl(s)$

Which is the required net ionic equation.

Best regards!

4 0

3 years ago

Which of these facts best illustrates why regulation of alcohol consumption is necessary

exis [7]

So that people don’t break laws or drive under the influence.

4 0

3 years ago