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3 years ago

Can someone help me, please?

Chemistry

1 answer:

VikaD [51]3 years ago

7 0

15. D is correct, exothermic reactions release heat

I am not sure about 16

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Which half-reaction correctly represents reduction?

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Answer choice C. Reduction has its electrons as a reactant.

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3 years ago

Whose main job is to break down sugar to release energy that a plant cell can use?

Tasya [4]

Answer:

The Mitochondria

Explanation:

Mitochondria are membrane-bound cell organelles that generate most of the energy required to power the cell's organic chemistry reactions. Energy created by the mitochondria is kept in a tiny molecule known as adenosine triphosphate (ATP).

3 0

3 years ago

Please help me with this. i also need to know what the word heat means.

aliina [53]

Heat is like the fire it’s hot.
I think it’s B
Sorry if I’m wrong

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2 years ago

Brass is a solid solution composed of zinc and copper. Brass is classified as a (n): A.colloid B.suspension C.solution D.alloy

melamori03 [73]

Brass is an alloy, or a combination of two (or more) metals.

4 0

3 years ago

When 0.620 gMngMn is combined with enough hydrochloric acid to make 100.0 mLmL of solution in a coffee-cup calorimeter, all of t

OleMash [197]

Answer:

The enthalpy change during the reaction is -199. kJ/mol.

Explanation:

$Mn(s)+2HCl(aq)\rightarrow MnCl_2(aq)+H_2(g)$

Mass of solution = m

Volume of solution = 100.0 mL

Density of solution = d = 1.00 g/mL

$m=1.00 g/mL\times 100.0 mL = 100 g$

First we have to calculate the heat gained by the solution in coffee-cup calorimeter.

$q=m\times c\times (T_{final}-T_{initial})$

where,

m = mass of solution = 100 g

q = heat gained = ?

c = specific heat = $4.18 J/^oC$

$T_{final}$ = final temperature = $23.1^oC$

$T_{initial}$ = initial temperature = $28.9^oC$

Now put all the given values in the above formula, we get:

$q=100 g \times 4.18 J/^oC\times (28.9-23.1)^oC$

$q=2,242.4 J=2.242 kJ$

Now we have to calculate the enthalpy change during the reaction.

$\Delta H=-\frac{q}{n}$

where,

$\Delta H$ = enthalpy change = ?

q = heat gained = 2.242 kJ

n = number of moles fructose = $\frac{\text{Mass of manganese}}{\text{Molar mass of manganese}}=\frac{0.620 g}{54.94 g/mol}=0.0113 mol$

$\Delta H=-\frac{2.242 kJ}{0.0113 mol }=-199. kJ/mol$

Therefore, the enthalpy change during the reaction is -199. kJ/mol.

8 0

2 years ago