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3 years ago

3) Summarize the ways the desert can help preserve a body.

1 answer:

Elena-2011 [213]3 years ago

8 0

3. Historically, bodies have been preserved naturally through freezing, cold or dry heat or, in the right climate, through burial in a particular type of soil.
4. They were not wrong but they are being improved by humans today.
5.true
6. False
7. True
8. True
11. The Egyptians invented and used many simple machines, such as the ramp and the lever, to aid construction processes. They used rope trusses to stiffen the beam of ships. Egyptian paper, made from papyrus, and pottery were mass-produced and exported throughout the Mediterranean basin.

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Using the following equation, 2C2H6 +7O2 -->4CO2 +6H2O, if 2.5g C2H6 react with 170g of O2, how many grams of water will be p

kirill [66]

The mass of water (H₂O) that would be produced is 4.5 g

<h3>Stoichiometry </h3>

From the question, we are to determine the mass of water that would be produced.

From the given balanced chemical equation

2C₂H₆ +7O₂ → 4CO₂ +6H₂O

This means

2 moles of C₂H₆ reacts with 7 moles of O₂ to produce 4 moles of CO₂ and 6 moles of H₂O

Now, we will determine the number of moles of each reactant present

For Ethane (C₂H₆)

Mass = 2.5 g

Molar mass = 30.07 g

Using the formula,

$Number\ of\ moles = \frac{Mass}{Molar\ mass}$

Number of moles of C₂H₆ present = $\frac{2.5}{30.07}$

Number of moles of C₂H₆ present = 0.08314 mole

For Oxygen (O₂)

Mass = 170g

Molar mass = 31.999 g/mol

Number of moles of O₂ present = $\frac{170}{31.999}$

Number of moles of O₂ present = 5.3127 moles

Since

2 moles of C₂H₆ reacts with 7 moles of O₂

Then,

0.08314 mole of C₂H₆ will react with $\frac{7 \times 0.08314 }{2}$

$\frac{7 \times 0.08314 }{2}$ = 0.58198 mole

Therefore,

0.08314 mole of C₂H₆ reacts with 0.58198 mole of O₂ to produce 3 × 0.08314 moles of H₂O

3 × 0.08314 = 0.24942 mole

Thus, the number of moles of water (H₂O) produced is 0.24942 mole

Now, for the mass of water that would be produced,

Using the formula,

Mass = Number of moles × Molar mass

Molar mass of water = 18.015 g/mol

Then,

Mass of water that would be produced = 0.24942 × 18.015

Mass of water that would be produced = 4.4933 g

Mass of water that would be produced ≅ 4.5 g

Hence, the mass of water (H₂O) that would be produced is 4.5 g

Learn more on Stoichiometry here: brainly.com/question/14271082

3 0

2 years ago

Which of the following statements is incorrect? A. Molecular mass is expressed in atomic mass units. B. Formula mass compares th

n200080 [17]

Answer:

The incorrect statement is the choice C. Atomic mass has units of grams per atom.

Explanation:

1) Choice A. Molecular mass is expressed in atomic mass units.

Correct. Atomic mass units (a.m.u) is the standard unit used to express the mass of the atoms and the molecules.

Since, one atom, molecule, or formula unit is a tiny amount of material, it has a ver, very low mass, and the unit mass of a molecule is referred to one mole (6.022 × 10²³ units).

2) Choice B. Formula mass compares the mass of one formula unit of a substance to the mass of one atom of carbon-12.

Correct. The masses of atoms and compounds are referred to a standard. Such standard is the carbon-12 atom. This is, the cabon-12 atom was selected as the standard and its exact mass is 12 a.m.u.

3) Choice C. Atomic mass has units of grams per atom.

Incorrect. Atomic mass is the mass of the atoms, but, since, the mass of one atom is so small, the atomic mass is referred to one mole. Hence, the atomic mass has units of grams per mole.

4) Choice D. Both molecular mass and formula mass use carbon-12 as a reference standard.

Correct. As stated when explaining the option B, the mass of atoms, molecules, and formula units are referred to carbon-12 standard.

5) Choice E. Sodium chloride, an ionic compound, is said to have a formula weight, but not a molecular weight.

Correct. The reason is that ionic compounds form large structures (crystals) and, since there is not such thing as one molecule of them, they are said to have formula weight (or mass) but not a molecular weight.

The name molecules is reserved for covalent compounds, where you can formally identify molecules. E.g. Water is a molecular compound, and each molecule has molecular formula H₂O, whose mass is the molecular mass.

7 0

3 years ago

Table salt is also known as sodium chloride, because it is

Mnenie [13.5K]

Sodom chloride is an ionic compound.

<h3>What is sodium chloride?</h3>

Sodium chloride is a compound that is formed by the combination of sodium and chlorine atoms. The compound is ionic as the ions of the atoms combine. Sodium looses one electron that can now be gained by chlorine.

Since the compound is ionic, it has a high melting and boiling point. This implies that the compound could melt as high as 801 degrees centigrade. The boiling point of the compound is much higher.

We can represent the compound using the ball and stick or the space filling model. The ball and stick model of sodium chloride has been shown in the image attached to this answer.

Learn more about ball and stick model:brainly.com/question/17217225

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