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tamaranim1 [39]
3 years ago
14

Which is an example of an endothermic reaction? A. combustion of fuels B. burning of wood C. cellular respiration D. photosynthe

sis E. nuclear explosion
Chemistry
2 answers:
kifflom [539]3 years ago
8 0

D. photosynthesis is an endothermic reaction

grandymaker [24]3 years ago
6 0

Answer: D. photosynthesis

Explanation:

Exothermic processes are those processes in which heat is released and endothermic processes are those processes in which heat is absorbed.

A. Combustion of fuels is an oxidation of hydrocarbons where energy is released.

B. Burning of wood is oxidation of carbon in which energy is released.

C. Cellular respiration is oxidation of food to release energy as ATP.

D. Photosynthesis is process of generation of food by green plants by use of sunlight as energy source.

E. Nuclear explosion involves nuclear reactions in which energy is released.

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How much heat is needed to raise the temperature of 100g of an iron from 25°C to
Black_prince [1.1K]

Answer:

382.5J

Explanation:

<em>Use the formula:</em>

E = mcΔθ or Q = mcΔT

m = 100g

c = 0.45 J/g°C

ΔT or Δθ = 110 - 25 = 85°

<em>Sub in the values:</em>

E = 100 × 0.45 × 85

= 382.5J

5 0
3 years ago
A buffer is composed of nh3 and nh4cl. How would this buffer solution control the ph of a solution when a small amount of a stro
Shkiper50 [21]

Answer:

According to Le-chatelier principle, equilibrium will shift towards left to minimize concentration of OH^{-} and keep same equilibrium constant

Explanation:

In this buffer following equilibrium exists -

NH_{3}(aq.)+H_{2}O(l)\rightleftharpoons NH_{4}^{+}(aq.)+OH^{-}(aq.)

So, OH^{-} is involved in the above equilibrium.

When a strong base is added to this buffer, then concentration of OH^{-} increases. Hence, according to Le-chatelier principle, above equilibrium will shift towards left to minimize concentration of OH^{-} and keep same equilibrium constant.

Therefore excess amount of OH^{-} combines with NH_{4}^{+} to produce ammonia and water. So, effect of addition of strong base on pH of buffer gets minimized.

5 0
3 years ago
Calculate the ph of a solution with a [H3O+]=5.6x10-9M
Kisachek [45]

Answer:

               pH  =  8.25

Explanation:

                   The acidity or basicity of a solution is measured by its pH. The pH scale ranges from 0 to 14. Solutions having pH from 0-6.9 are considered acidic, at 7 neutral and basic when ranging from 7.1-14.

pH is calculated as,

                                 pH  =  - log [H⁺]   ---- (1)

Where;

            [H⁺]  =  concentration of Acid

Also, for bases pH i calculated using following formula,

                                 pH  =  14 - pOH

Therefore, Putting value of H⁺ in equation 1,

                                 pH  =  - log [5.6 × 10⁻⁹]

                                pH =  8.25

The solution provided is basic in nature.

6 0
3 years ago
HELP TIMED !!!!
Troyanec [42]
Hello there what is the question?

6 0
3 years ago
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What is a cylinder? Give an example of an<br> object that's a cylinder.
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By definition a cylinder is a solid geometric figure with straight parallel sides and a circular or oval cross-section. A good example of a cylinder would be a soda can.
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3 years ago
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