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2 years ago

Calculate the mass (in grams) of cobalt that has the same number of atoms as 521 mg of silicon.

1 answer:

8 0

The atomic mass of silicon is 28 g/mol.
Therefore, 521 mg or 0.521 g will be equivalent to;
0.521/28 = 0.01861 mooles
Atomic mass of cobalt is 27 g/mol
According to Avogadro's law the mass of cobalt that will have the same atom as 52 mg of silicon will be ;
(0.01861 moles × 27) = 0.5024 g or 502.4 mg

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A student determines measures the mass of one mole of carbon and finds it to be 12.22 grams. if the accepted value is 12.11 gram

Gre4nikov [31]

Answer:-

0.91% is the students % of error

Explanation: -

Accepted value= 12.11 grams

Measured value = 12.22 grams

Error = 12.22-12.11 = 0.11 grams

Percentage error = $\frac{0.11 grams}{12.11 grams}$ x100

= 0.91 %

Thus 0.91% is the students % of error

5 0

2 years ago

Gaseous ICl (0.20 mol) was added to a 2.0 L flask and allowed to decompose at a high temperature:

Ne4ueva [31]

Answer:

The Kc is 1.36 (but this is not an option, may be the options are wrong, or may be I was .. Thanks!)

Explanation:

Let's think all the situation.

2 ICl(g) ⇄ I₂(g) + Cl₂(g)

Initially 0.20 - -

Initially I have only 0.20 moles of reactant, and nothing of products. In the reaction, an x amount of compound has reacted.

React x x/2 x/2

Because the ratio is 2:1, in the reaction I have the half of moles.

So in equilibrium I will have

(0.20 - x) x/2 x/2

Notice that I have the concentration in equilibrium so:

0.20 - x = 0.060

x = 0.14

So in equilibrium I have formed 0.14/2 moles of I₂ and H₂ (0.07 moles)

Finally, we have to make, the expression for Kc and remember that must to be with concentration in M (mol/L).

As we have a volume of 2L, the values must be /2

Kc = ([I₂]/2 . [H₂]/2) / ([ICl]/2)²

Kc = (0.07/2 . 0.07/2) / (0.060/2)²

Kc = 1.225x10⁻³ / 9x10⁻⁴

Kc = 1.36

8 0

2 years ago

Compute the end-to-end separation (direct distance between molecule ends), in Angstroms, of a coiled PVC molecule with a number-

MArishka [77]

Answer:

5156 Â

Explanation:

Chains of monomers that are being linked together constitute what is called polymers. in this question; we are to compute the end to end separation (direct distance between molecule ends), in Angstroms, of a coiled PVC molecule.

Using the following approach:

The first step is to determine the repeating units in polymer

The number of repeating unit = average molecular weight/ atomic weight of PVC

Given that:

average molecular weight = 256,131 g/mol

atomic weight of PVC = 62.498 g

Then;

The number of repeating unit = 256,131 g/mol / 62.498 g = 4098.227143 mol

Now the distance is calculated by using the formula:

d = (C-C) × sin 109.5/2

C-C bond length = 1.54 angstroms

tetrahedral bond angle = 109.5°

Then d = (1.54) × sin 109.5/2

d = 1.258

Thus ; the end to end separation is :

4098.227143 × 1.258 = 5155.57 Â

The answer is 5156 Â (since no decimal should be included )

6 0

2 years ago

This is a document that each chemical manufacturer, distributor, or importer must provide for each hazardous chemical. It contai

kkurt [141]

Answer : HazCom

Explanation : Hazard communication which is also known as HazCom, is a set of processes and procedures that every employers and importers must implement in their workplace to effectively communicate hazards associated with chemicals during handling, shipping, and any form of exposure.

The OSHA Hazard Communication Standard is a U.S. regulation which governs the evaluation and communication of hazards associated with chemicals at the workplace. It is typically not attached to any specific chemical container but is stored in the workplace.

7 0

2 years ago

Read 2 more answers

The pOH of a solution is 6.0. Which statement is correct? Use p O H equals negative logarithm StartBracket upper O upper H super

Katen [24]

Answer:

The pH of the solution is 8.

Explanation:

To which options are correct, let us determine the concentration of the hydroxide ion, [OH-] and the pH of the solution. This is illustrated below:

1. The concentration of the hydroxide ion, [OH-] can be obtained as follow:

pOH = –Log [OH-]

pOH = 6

6 = –Log [OH-]

–6 = Log [OH-]

[OH-] = Antilog (–6)

[OH-] = 1x10^–6 mol/L

2. The pH of the solution can be obtained as follow:

pH + pOH = 14

pOH = 6

pH + 6 = 14

pH = 14 – 6

pH = 8.

From the calculations made above,

[OH-] = 1x10^–6 mol/L

pH = 8.

Therefore, the correct answer is:

The pH of the solution is 8

3 0

2 years ago