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2 years ago

The mass of an object is 205 gram while the volume was measured to be 82.5 mL. What is this object's density?

Chemistry

1 answer:

aniked [119]2 years ago

5 0

2.48 g/mL

Density = mass/volume = (205 g)/(82.5 mL) = 2.48 g/mL

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Rocks formed by changes in heat and pressure or the presence of hot, watery fluids

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If you're looking for "what rocks are formed by changes..." it's Igneous Rocks.

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2 years ago

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In molecules, energy is stored in? Atoms Electrons The Nucleus Bonds

Nikolay [14]

Answer:

Atoms

Explanation:

Energy, potential energy, is stored in the covalent bonds holding atoms together in the form of molecules. This is often called chemical energy.

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2 years ago

What methods were used to clean up the Chernobyl and three mile island accidents?

Assoli18 [71]

Answer:

Electric evaporator has been used to clean up the Chernobyl and 3 mile island accident.

Explanation:

About 14 years back, there was a puff of radioactive steam from the evaporator used in the "Three-mile island" nuclear plant. It took two years for the electric evaporator to clean up the 2.2 million gallons of water that have been destroyed because of the nuclear power plant accident.

The steam that came out of the electric evaporator carried a radioactive form of hydrogen and tritium with itself. Cost of clean up was $1 billion.

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2 years ago

Hydrogen cyanide, HCN, is prepared from ammonia, air, and natural gas (CH₄), by the following process:

kykrilka [37]

Answer:

6.75 g of HCN can be produced by the reaction

Explanation:

Complete reaction is:

2NH₃ (g) + 3O₂ (g) + 2CH₄ (g) → 2HCN (g) + 6H₂O (g)

Let's determine the moles of each reactant:

11.5 g . 1mol / 17g = 0.676 moles of ammonia

12 g . 1 mol / 32g = 0.375 moles of oxygen

10.5 g . 1mol/ 16 g = 0.656 moles of methane

Now is all about rules of three:

2 moles of ammonia reacts with 3 moles of O₂ and 2 moles of methane

0.676 moles of NH₃ may react with:

(0.676 . 3) /2 = 1.014 moles of O₂

(0.676 . 2) / 2 = 0.676 moles of methane

Both can be the limiting reactant.

3 moles of O₂ react with 2 moles of NH₃ and 2 moles of methane

0.375 moles of O₂ will react with:

(0.375 .2) / 3 = 0.375 moles

The same amount for methane, 0.375 moles

2 moles of CH₄ reacts with 3 moles of O₂ and 2 moles of NH₃

0.656 moles of methane would react with 0.656 moles of NH₃

(0.656 . 3 ) /2 = 0.437 moles of O₂ I do not have enough O₂

Oxygen is the limiting reactant → We can work with the reaction now.

Ratio is 3:2. 3 moles of oxygen produce 2 moles of cyanide

0.375 moles of O₂ may produce (0.375 .2 ) / 3 = 0.250 moles

If we convert the moles to mass → 0.250 mol . 27 g / 1mol = 6.75 g

4 0

2 years ago

. how many lone pairs of electrons are present in the lewis structure of calcium sulfide?

miv72 [106K]

Answer:
Four

Explanation:
Calcium Sulfide is an ionic compound made up of Ca²⁺ and S²⁻.
Ca²⁺ is formed as,

Ca → Ca²⁺ + 2 e⁻

These two electrons are accepte by Sulfur as,

S + 2 e⁻ → S²⁻

So, before accepting 2 electrons S was having six valence electrons, after accepting two electrons from Ca it has 8 electrons which are present in four pairs as shown below,

7 0

2 years ago