Can anyone answer these?

Chemistry

1 answer:

Maurinko [17]3 years ago

8 0

Answer:

18 is a

19 is c

20 i am not sure

Explanation:

18)nucleus contains protons and neutrons

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A single covalent bond is made up of

SIZIF [17.4K]

Answer:

In chemistry, a single bond is a chemical bond between two atoms involving two valence electrons. That is, the atoms share one pair of electrons where the bond forms. Therefore, a single bond is a type of covalent bond.

Explanation:

(copied from Google)

4 0

3 years ago

I need help ASAP! How many reactants and products are in each element according to the chemical equation above.

Len [333]

Answer:

O 4

C 1

1 sodium

3 H

Products

1 sodium

3 H

4 O

1 C

Explanation:

7 0

3 years ago

1 C8H10(l) +21/2O2(g) → 8CO2(g) + 5H2O(g), Hcomb= ? Hf for C8H10(l) = +49.0kJ/mol C8H10(l) Use the balanced combustion reaction

nikklg [1K]

Answer:

$H_{comb}=-4406kJ/mol$

Explanation:

Hello,

In this case, the enthalpy of combustion is understood as the energy released when one mole of fuel, in this case octene, is burned in the presence of oxygen and is computed with the enthalpies of formation of the fuel, carbon dioxide and water as shown below (oxygen is circumvented as it is a pure element):

$H_{comb}=8*\Delta _fH_{CO_2}+5\Delta _fH_{H_2O}-\Delta _fH_{C_8H_{10}}$

Thus, since we already know the enthalpy of combustion of the fuel, for carbon and water we have -393.5 and -241.8 kJ/mol respectively, thereby, the enthalpy of combustion turns out:

$H_{comb}=8*(-393.5kJ/mol)+5(-241.8kJ/mol)-49.0kJ/mol\\\\H_{comb}=-4406kJ/mol$