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3 years ago

Which process results in a chemical change?

Chemistry

2 answers:

pashok25 [27]3 years ago

8 0

<span> burning magnesium ribbon</span>

Alla [95]3 years ago

5 0

D) burning magnesium ribbon, as combustion is a chemical reaction so causes chemical change. The other 3 options do not involve reactions so there isn't a chemical change.

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Consider these equations: 2S(s)+3O2(g)→2SO3(g) , ΔH=−792kJ 2S(s)+2O2(g)→2SO2(g) , ΔH=−594kJ 2SO2(g)+O2(g)→2SO3(g) , ΔH=? What is

Elenna [48]

Hess law can help us to obtain the enthalpy of a series of reactions by summation. The missing enthalpy of this reaction is −198kJ.

According to the Hess law of constant heat summation, the enthalpy of a sequence of reactions can be obtained as the sum of the enthalpies of all the reactions.

Now looking at all the reavtion written here in order to obtain the missing enthalpy, we conclude that the missing enthalpy is −198kJ.

Learn more about enthalpy: brainly.com/question/3393755

6 0

2 years ago

You wish to measure the iron content of the well water on the new property you are about to buy. You prepare a reference standar

djverab [1.8K]

1.04 ⨯ 10 $^{-4}$ M

<h3>Explanation</h3>

<em>A</em> = <em>ε</em> $\cdot l \cdot c$ by the Beer-Lambert law, where

<em>A</em> the absorbance,
$l$ the path length,
<em>ε</em> the molar absorptivity of the solute, and
$c$ concentration of the solution.

<em>A</em> and <em>ε </em>are the same for both solutions. Therefore, $l \cdot c$ is constant; $l$ is inversely proportional to $c$ . The 100 mL sample would have a concentration 1/4.78 times that of the 45.0 mL reference.

The 13.0 mL standard solution has a concentration of 5.17 ⨯ $10^{-4}$ M. Diluting it to 45.0 mL results in a concentration of $5.17 \times 10^{-4} \times \frac{13.0}{45.0} =$ 1.494 M.

$c$ is inversely related to $l$ for the two solutions. As a result, c₂ = $c_1 \cdot \frac{l_1}{l_2} = 1.494 \times 10^{-4} \times \frac{1}{4.78} =$ 3.126 M.

The 30.0 mL sample has to be diluted by 30.0 / 100.0 times to produce the 100.0 mL solution being tested. The 100.0 mL solution has a concentration of 3.126 M. Therefore, the 30.0 mL solution has a concentration of $3.126 \times \frac{100.0}{30.0} =$ 1.04 ⨯ $10^{-4}$ M.

6 0

3 years ago

Why does the moon spin around the earth and the earth spins around the sun

liberstina [14]

This easy bro there is only one answer Gravity

but here my advance word

Sometimes the gravity of big objects would capture smaller ones in orbit. This could be one way the planet acquired the moon

7 0

4 years ago

Who believed that a grain of sand could be divided indefinitely?

Ilya [14]

Answer:

Democritus

Explanation:

4 0

3 years ago

1.A telescope is a tool that helps people observe distant objects. In the simplest telescope design, incoming light hits a lens

Dahasolnce [82]

Answer:

it is refraction

Explanation:

7 0

3 years ago