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iris [78.8K]
3 years ago
7

How many moles are equal to a 0.25g sample of chromium?

Chemistry
1 answer:
jonny [76]3 years ago
7 0

Answer:

0.0048 mol Cr

Explanation:

Step 1: Define

Molar Mass of Chromium (Cr) - 52.00 g/mol

Step 2: Use Dimensional Analysis

0.25 \hspace{3} g \hspace{3} Cr(\frac{1 \hspace{3} mol \hspace{3} Cr}{52.00 \hspace{3} g \hspace{3} Cr} ) = 0.004808 mol Cr

Step 3: Simplify

We are give 2 sig figs.

0.004808 mol Cr ≈ 0.0048 mol Cr

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If a solid has a density of 4.0 g/cm^3, what volume of the solid has a mass<br> of 24 g? Show work.
Mrrafil [7]

Answer:

<h2>Volume = 6 cm³</h2>

Explanation:

Density of a substance is given by

Density =  \frac{mass}{volume}

From the question

Density = 4.0 g/cm³

mass = 24g

Substitute the values into the above formula and solve for the volume

That's

4 =  \frac{24}{v}  \\4v = 24

Divide both sides by 4

v = 6

We have the final answer as

<h3>Volume = 6 cm³</h3>

Hope this helps you

8 0
3 years ago
15. Which compounds are reactants in the process of cellular respiration?
scoundrel [369]

Answer: the correct answer would be the last option, C6H12O6 and O2

Explanation:

5 0
2 years ago
An ideal gaseous reaction (which is a hypothetical gaseous reaction that conforms to the laws governing gas behavior) occurs at
lana [24]

Answer:

ΔU = −55.45 kJ

Explanation:

From first law of thermodynamics in chemistry, we have;

ΔU = Q + W

where;

ΔU is change in internal energy

Q is the net heat transfer

W is the net work done

We are given;

Q = 74.6 kJ

But Q will be negative since heat is released

Thus;

ΔU = -74.6 kJ + W

We are given;

Constant pressure; P = 35 atm = 35 × 101325 = 3546375 N/m²

Volume before reaction; Vi = 8.2 L = 0.0082 m³

Volume after reaction; V_f = 2.8 L = 0.0028 m³

Now,

W = -P(V_f - V_i)

W = - 3546375(0.0028 - 0.0082)

W = 19.15 KJ

Thus;

ΔU = Q + W

ΔU = -74.6 kJ + 19.15 KJ =

ΔU = −55.45 kJ

6 0
2 years ago
Given the balanced equation representing a reaction:
Vladimir79 [104]

Answer:

Option A. Addition

Explanation:

Unsaturated compounds under goes addition reaction to produce saturated compounds..

In the equation given above i.e

H2C=CH2 + F–F —> FCH2CH2F

we can see that the double in H2C=CH2 disappear by the reaction of F–F to produce FCH2CH2F which has no double. This simply indicates that the F–F was added to H2C=CH2. Hence, the reaction is called addition reaction.

4 0
3 years ago
Which of the following is true in regard to ions? A. A cation will hold a positive charge if it gains one or more electrons. B.
tigry1 [53]

Answer:

B. An ionized atom has a number of protons that is unequal to the number of electrons.

Explanation:

For a neutral atom , the number of proton and electron is equal. An ionized atom has either loss or gain electron, thereby making the number of proton and electron unequal. The answer B is true because an ionized atom has either loss or gain electron to make the number of electron and proton unequal.

Option A is incorrect because a cations holds a positive charge when it loss one or more electron not when it gains one or more electron(s). Anions possess negative charge for gaining electron(s).

Option C is not true because ions can also carry negative charges and they are called anions.

Option D is false because losing one or more electron will turn an atom to a cations.

7 0
3 years ago
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