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3 years ago

How many molecules are in 3.0 moles of O2

1 answer:

5 0

Answer: " <span>1.8 * 10²⁴ molecules of O₂ " .
________________________________________</span>

3.0 moles O₂ * (6.02 * 10²³ molecules O₂ / 1 mol O₂) =

[ (3.0) *(6.02 * 10²³) ] molecules O₂
= 1.806 * 10²⁴ ; round to 2 significant figures.
= 1.8 * 10²⁴ molecules of O₂ .
______________________________________________________

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3. Determine the uses of the following materials:

hichkok12 [17]

Answer:

Explanation:

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3 years ago

In which state of matter do particles have the least amount of energy

kogti [31]

Answer:

solid

Explanation:

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3 years ago

Calculate the molarity of hydroxide ion in an aqueous solution that has a poh of 5.00

Simora [160]

Answer:

1.00 x 10^-5 M

Explanation:

pOH=-log[OH^-]

[OH^-]=10^(-pOH)

=10^-5

=1.00 x 10^-5 M

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3 years ago

New questionWhat mass of calcium chloride (CaCl₂) would beproduced from the reaction of 125.9 g of hydrochloriacid (HCI) with ex

marshall27 [118]

Answer:

191.6 g of CaCl₂.

Explanation:

What is given?

Mass of HCl = 125.9 g.

Molar mass of CaCl₂ = 110.8 g/mol.

Molar mass of HCl = 36.4 g/mol.

Step-by-step solution:

First, we have to state the chemical equation. Ca(OH)₂ react with HCl to produce CaCl₂:

$Ca(OH)_2+2HCl\rightarrow CaCl_2+2H_2O.$

Now, let's convert 125.9 g of HCl to moles using the given molar mass (remember that the molar mass of a compound can be found using the periodic table). The conversion will look like this:

$125.9\text{ g HCl}\cdot\frac{1\text{ mol HCl}}{36.4\text{ g HCl}}=3.459\text{ moles HCl.}$

Let's find how many moles of CaCl₂ are being produced by 3.459 moles of HCl. You can see in the chemical equation that 2 moles of HCl reacted with excess Ca(OH)₂ produces 1 mol of CaCl₂, so we state a rule of three and the calculation is:

$3.459\text{ moles HCl}\cdot\frac{1\text{ mol CaCl}_2}{2\text{ moles HCl}}=1.729\text{ moles CaCl}_2.$

The final step is to find the mass of CaCl₂ using the molar mass of CaCl₂. This conversion will look like this:

$1.729\text{ moles CaCl}_2\cdot\frac{110.8\text{ g CaCl}_2}{1\text{ mol CaCl}_2}=191.6\text{ g CaCl}_2.$

The answer would be that we're producing a mass of 191.6 g of CaCl₂.

4 0

1 year ago

The temperature of a sample of water changes from 10°C to 20°C when the water absorbs 100 calories of heat. What is the mass of

Vlad1618 [11]

Answer:

10 g

Explanation:

Right from the start, just by inspecting the values given, you can say that the answer will be

10 g

Now, here's what that is the case.

As you know, a substance's specific heat tells you how much heat is needed to increase the temperature of

1 g

of that substance by

∘

Water has a specific heat of approximately

4.18

∘

. This tells you that in order to increase the temperature of

1 g

of water by

∘

, you need to provide

4.18 J

of heat.

Now, how much heat would be required to increase the temperature of

1 g

of water by

∘

Well, you'd need

4.18 J

to increase it by

∘

, another

4.18 J

to increase it by another

∘

, and so on. This means that you'd need

4.18 J

41.8 J

to increase the temperature of

1 g

of water by

∘

Now look at the value given to you. If you need

41.8 J

to increase the temperature of

1 g

of water by

∘

, what mass of water would require

times as much heat to increase its temperature by

∘

1 g

10 g

And that's your answer.

Mathematically, you can calculate this by using the equation

⋅

, where

- heat absorbed/lost

- the mass of the sample

- the specific heat of the substance

- the change in temperature, defined as final temperature minus initial temperature

Plug in your values to get

418

⋅

4.18

∘

⋅

(

−

)

∘

418

4.18

⋅

10 g

5 0

3 years ago