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makkiz [27]
3 years ago
15

Select all of the following equations that represent an exothermic reaction.

Chemistry
1 answer:
masya89 [10]3 years ago
6 0

Answer:

C(graphite) → C(diamond), ΔH = - 0.45 kcal

CH4 + 2O2 → CO2 + 2H2O + 212,800 cal

Explanation:

C(graphite) → C(diamond), ΔH = - 0.45 kcal

CH4 + 2O2 → CO2 + 2H2O + 212,800 cal

These reactions are exothermic reaction because heat is evolved.

The energy changes occur during the bonds formation and bonds breaking.

There are two types of reaction endothermic and exothermic reaction.

Endothermic reactions:

The type of reactions in which energy is absorbed are called endothermic reactions.

In this type of reaction energy needed to break the bond are higher than the energy released during bond formation.

For example:

C + H₂O   →  CO  + H₂

ΔH = +131 kj/mol

it can be written as,

C +  H₂O  + 131 kj/mol  →  CO  + H₂

Exothermic reaction:

The type of reactions in which energy is released are called exothermic reactions.

In this type of reaction energy needed to break the bonds are less than the energy released during the bond formation.

For example:

Chemical equation:

C + O₂   →  CO₂

ΔH = -393 Kj/mol

it can be written as,

C + O₂   →  CO₂ + 393 Kj/mol

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3 years ago
What is the mass, in grams, of
DIA [1.3K]

Answer:

The answers to your question are below

Explanation:

a) 6.85×1020 H2O2 molecules

H2O2   MW = 32 + 2 = 34 g

                                    34g -------------------- 6.023 x 10²³ molecules

                                    x       -------------------  6.85 x 10 ²⁰

                                   x = (6.85 x 10 ²⁰)(34)/  6.023 x 10²³

                                   x = 0.038 g

3.3×1022 SO2 molecules

MW SO2 = 32 + 32 = 64g

                                    64 g -------------------- 6.023 x 10²³ molecules

                                    x      --------------------  3.3×1022 SO2 molecules

                                    x = (3.3×1022 SO2)(64) / 6.023 x 10²³

                                   x = 3.51 g

5.5×1025 O3 molecules

MW = 16 x 3 = 48g

                                 48 g -----------------   6.023 x 10²³ molecules

                                  x     ------------------   5.5×1025 O3 molecules

                               x = (5.5×1025 )(48) /  6.023 x 10²³

                               x = 4383 g

9.30×1019 CH4 molecules

MW = 12 + 4 = 16 g

                              16 g --------------------  6.023 x 10²³ molecules

                              x      --------------------   9.30×1019 CH4 molecules

                           x = (9.30×1019)(16) / 6.023 x 10²³

                           x = 0.0025 g

4 0
2 years ago
If the relative humidity is high and the temperature drops, water vapor may
meriva

If the water vapor content stays the same and the temperature drops, the relative humidity increases. If the water vapor content stays the same and the temperature rises, the relative humidity decreases. This is because colder air doesn't require as much moisture to become saturated as warmer air.

6 0
3 years ago
Vaporized water is also known as
viva [34]

Answer:

fog

Explanation:

4 0
2 years ago
Balance the following equation. Then, given the moles of reactant or product below, determine the corresponding amount in moles
Mrrafil [7]

Answer:

Option a → 4 mol NH₃

Explanation:

This the unbalanced reaction

NH₃  +  O₂  ⟶  N₂  +  H₂O

The balanced reaction:

4NH₃  +  3O₂  →  2N₂  +  6H₂O

4 mol of ammonia

3 mol of oxygen

2 mol of nitrogen

6 mol of water

6 0
3 years ago
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