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3 years ago

Lunar Eclipe's do not happen every month because the moon, earth and sun must be lined up in a certain way.

Chemistry

2 answers:

chubhunter [2.5K]3 years ago

5 0

True

Thank you for you time

Andreyy893 years ago

4 0

Answer:

A. True

Explanation:

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Magnesium and iron are metallic elements. How does a mole of magnesium compare with a mole of iron?

Alexus [3.1K]

Given a mole each for iron and magnesium, the number of atoms of each element is equal. Iron has a greater mass due to its greater molecular weight. The correct statement among the choices is D.

6 0

3 years ago

Read 2 more answers

True or False: In a compound, the combination of elements is always different

dmitriy555 [2]

Answer:

in some cases this is true a compound is a mixture of elements although it is actualy false the diffrence is actualy baced on what elements it is made of like sulfur Dioxide is when sulfur reacts with the contents of the air when burning and reacting but they arnt always diffrent most caces it is just what element you use.

Explanation:

7 0

3 years ago

Determine ΔH for the reaction CaCO3 → CaO + CO2 given these data: 2 Ca + 2 C + 3 O2 → 2 CaCO3 ΔH = −2,414 kJ C + O2 → CO2 ΔH = −

kicyunya [14]

Answer:

The ΔH for the reaction is -456.5 KJ

Explanation:

Here we want to determine ΔH for the reaction;

Mathematically;

ΔH = ΔH(product) - ΔH(reactant)

In the case of the first reaction;

ΔH = ΔH(CaO) + ΔH(CO2) - ΔH(CaCO3) ...........................(*)

From the other reactions, we can get the respective ΔH for the individual molecule in the reaction

In second reaction;

Kindly note that for elements, molecule of gases, ΔH = 0

What this means is that throughout the solution;

ΔH(Ca) = 0 KJ

ΔH(O2) = 0 KJ

ΔH(C) = 0 KJ

Thus, in writing the equation for the subsequent chemical reactions, we shall need to write and equate the overall ΔH for the reaction to that of the product alone

So in the second reaction

ΔH = 2ΔH(CaCO3)

Thus;

-2414/2 = ΔH(CaCO3)

ΔH(CaCO3) = -1,207 KJ

Moving to the third reaction, we have;

ΔH = ΔH(CO2)

Hence ΔH(CO2) = -393.5 KJ

For the last reaction;

ΔH = ΔH(CaO)

Hence ΔH(CaO) = -1270 KJ

Going back to equation *

ΔH = ΔH(CaO) + ΔH(CO2) - ΔH(CaCO3)

Using the values of the ΔH of the respective molecules given above,

ΔH = -1270 + (-393.5) - (-1207)

ΔH = -456.5 KJ

8 0

3 years ago

You measure salt water in a tank to have a density of 1.02 g/mL. A balloon weighs 2.0 g and you weights have a mass of 30.0 g ea

Elden [556K]

Weight of the balloon = 2.0 g

Six weights each of mass 30.0 g is added to the balloon.

Total mass of the balloon = 2.0 g + 6*30.0 g = 182 g

Density of salt water = 1.02 g/mL

Calculating the volume from mass and density:

$182g*\frac{mL}{1.02g} =178mL$

Converting the volume from mL to cubic cm:

$178 mL * \frac{1cm^{3} }{1mL} =178cm^{3}$

Assuming the balloon to be a sphere,

Volume of the sphere = $\frac{4}{3}$ π $r^{3}$

$178 cm^{3} = \frac{4}{3}(\frac{22}{7})r^{3}$

r = 3.49 cm

Radius of the balloon = 3.49 cm

Diameter of the balloon = 2 r = 2*3.49 cm = 6.98cm

4 0

3 years ago

Does acid rain make new substances? Construct an argument that uses data from this investigation as evidence for your claim.

Yuri [45]

Answer:

Acid rain, like all acids, generates dissolution of chemical compounds, and reacts together with bases to be able to carry out oxide reduction reactions, which by deduction is very likely to form new substances as a result of the dissolution or acid erosion caused.

Explanation:

Acid rain is more likely to occur in large cities or large sources of pollution, since the excess of carbon dioxide in the atmosphere causes it to increase its partial pressure in a condensed way in the clouds, this is how then this cloud when being loaded with water and then generating the rain drags these masses of condensed carbon dioxide in the form of acid rain.

The degree of acidity is directly proportional to the amount of partial pressure of carbon dioxide in the atmosphere.

5 0

3 years ago