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3 years ago

Every pure substance has exact and specific density. What are two purposes that a chemist would use a calculated density for.

Chemistry

1 answer:

adell [148]3 years ago

7 0

Answer:

1. Density can be used to identify a substance

2. Density can be used to ascertain whether a substance will float in water.

Explanation:

The calculation of the density of a substance can be used to identify the substance. If the density of a substance is calculated accurately, and compared with a table of standard densities, then we can identify that substance.

Also, density determines whether an object will float or sink in water. If an object is less dense than water then it will float in water. If it is denser than water, then it will sink in water.

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You find a compound composed only of element X and chlorine and you know that the compound is 13.10% X by mass. Each molecule of

8_murik_8 [283]

Answer:

Explanation:

So, the formula for the compound should be:

$XCl_{6}$

Now we assume that we have 1 mol of substance, so we can make calculations to know the molar mass of element X, as follows:

$M_{Cl}=35.45g/mol\\$

So we have that 6 moles weight 212.7g, and we can make a rule of three to know the weight of compound X:

$212.7g\rightarrow 86.9\%\\x\rightarrow 13.1\%\\\\x=\frac{212.7g*13.1}{86.9} =32.06g$

As we used 1 mol, we know that the molar mass is 32.06g/mol

So the element has a molar mass of 32.06 g/mol and an oxidation state of +6, with this information, we can assure that the element X is sulfur, so the compound is $SCl_{6}$

8 0

3 years ago

Phenolphthalein has a pKa of 9.7 and is colorless in its acid form and pink in its basic form. calculate [In-}/{HIn} for the fol

zvonat [6]

Answer:

1.58x10⁻⁵

2.51x10⁻⁸

0.0126

63.10

Explanation:

Phenolphthalein acts like a weak acid, so in aqueous solution, it has an acid form HIn, and the conjugate base In-, and the pH of it can be calculated by the Handerson-Halsebach equation:

pH = pKa + log[In-]/[HIn]

pKa = -logKa, and Ka is the equilibrium constant of the dissociation of the acid. [X] is the concentrantion of X. Thus,

i) pH = 4.9

4.9 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = - 4.8

[In-]/[HIn] = $10^{-4.8}$

[In-]/[HIn] = 1.58x10⁻⁵

ii) pH = 2.1

2.1 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = -7.6

[In-]/[HIn] = $10^{-7.6}$

[In-]/[HIn] = 2.51x10⁻⁸

iii) pH = 7.8

7.8 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = -1.9

[In-]/[HIn] = $10^{-1.9}$

[In-]/[HIn] = 0.0126

iv) pH = 11.5

11.5 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = 1.8

[In-]/[HIn] = $10^{1.8}$

[In-]/[HIn] = 63.10

6 0

3 years ago

How many degrees of unsaturation are lost or gained in the base-induced transformation from mito-ph to its photoactive ring-open

Fudgin [204]

Unsaturation (IHD) 2 hydrogen Needed

IHD = [(2n+2) -H]/2
(H: X=1, N=-1, O= zero)

Unsaturation:
Double bonds = 1
Rings = 1
Triple Bonds = 2

The degrees of unsaturation in a molecule are additive — a molecule with one double bond has one degree of unsaturation, a molecule with two double bonds has two degrees of unsaturation, and so forth.

6 0

3 years ago

Identify the terms described by selecting the correct word from the drop-down menu.

Ksju [112]

Answer: Matter

Biosphere

Explanation:

7 0

2 years ago

The town in the video stressed using locally made goods instead of imported goods. How could using locally made goods lower CO2

ladessa [460]

Answer:

It reduces the need to import goods

Explanation:

When you buy locally, the products you buy don't come from far away, so they don't have to cross the country (or the ocean) by boat, plane or trucks to reach the market/store where you're buying, at least not from a long distance away.

The distance a vehicle travels, the less CO2 emissions it produces.

If the good you're buying is made/produced only an hour away, that's not much pollution produced compared as if the good has to come from a distant place spending days on highways to reach you.

6 0

3 years ago