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2 years ago

How many atoms of gold are in a pure gold coin weighing 12.0g?

1 answer:

3 0

12.0g x 1 mol / 63.546g = 0.188839581mol

<span>So, for every 1 mole, we have 6.022 x 10^23 of whatever we're measuring. This gives us a conversion factor of (1 mole / 6.022 x 10^23 atoms) or (6.022 x 10^23 atoms / 1 mole).
</span>
0.188839581 mol x (6.022 x 10^23 atoms) / 1 mol = 1.137191955 x 10^23

<span>Remember from before that we are limited to 3 significant figures. Since our calculations are complete, we can now round down to: 1.14 x 10^23 </span>

<span>That should be your answer!

Hope it helps!
xo</span>

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When you apply 1000 joules of energy to 50 grams of water its temperature changes to 30 degrees . What was the initial temperatu

expeople1 [14]

Answer:

25.2°C

Explanation:

Given parameters:

Energy applied to the water = 1000J

Mass of water = 50g

Final temperature = 30°C

Unknown:

Initial temperature = ?

Solution:

To solve this problem, we use the expression below:

H = m c Ф

H is the energy absorbed

m is the mass

c is the specific heat capacity

Ф is the change in temperature

1000 = 50 x 4.184 x (30 - initial temperature )

1000 = 209.2(30 - initial temperature)

4.78 = 30 - initial temperature

4.78 - 30 = - initial temperature

Initial temperature = 25.2°C

7 0

2 years ago

6 Fe2+ (aq) + Cr2O72− (aq) + 14 H+ (aq) → 6 Fe3+ (aq) + 2 Cr3+ (aq) + 7 H2O (aq) If the titration of 23 mL of an iron(II) soluti

ratelena [41]

Answer:

1.047 M

Explanation:

The given reaction:

$6Fe^{2+}_{(aq)}+Cr_2O_7^{2-}_{(aq)}+14H^+_{(aq)}\rightarrow 6Fe^{3+}_{(aq)}+2Cr^{3+}_{(aq)}+7H_2O_{(aq)}$

For dichromate :

Molarity = 0.254 M

Volume = 15.8 mL

The conversion of mL to L is shown below:

1 mL = 10⁻³ L

Thus, volume = 15.8 ×10⁻³ L

Thus, moles of dichromate :

$Moles=0.254 \times {15.8\times 10^{-3}}\ moles$

Moles of dichromate = 0.0040132 moles

1 mole of dichromate react with 6 moles of iron(II) solution

Thus,

0.0040132 moles of dichromate react with 6 × 0.0040132 moles of iron(II) solution

Moles of iron(II) solution = 0.02408 moles

Volume = 23 mL = 0.023 L

Considering:

$Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}$

<u>Molarity = 0.02408 / 0.023 = 1.047 M</u>

7 0

2 years ago

What are the relationships between melting and freezing of a mixture

Kaylis [27]

The temperature is the same but the heat flow is the opposite.

4 0

2 years ago

Recall rem = rad x q radiation weighting factor (q): the ability to transfer energy to the body 1 for photons 1 for electrons 2

tino4ka555 [31]

The biological risk for the first person than the second as a result of radiation weighting is 10 times.

<h3>What is radiation weighting factor?</h3>

As stated in the question, radiation weighting factor (q) is the ability to transfer energy to the body.

If radiation factor of proton = 2, and radiation factor of alpha particles = 20.

First person is exposed to alpha radiation = 20
Second person is exposed to protons = 2

Risk of first person with respect to second person = 20/2 = 10 times higher

Learn more about radiation factor here: brainly.com/question/24039736

#SPJ4

6 0

1 year ago

What is the difference between Renewable Energy and Non renewable Energy? Which one is better for the environment and why? Also

goblinko [34]

Answer:

The difference between them is that renewable energy is something that can be used practically and not run out. Non-renewable energy has a limited supply.

Explanation:

Renewable energy is better for the environment as it is not something that takes millions of years to form, as some non-renewable energy sources are.

Brainliest please! :>

6 0

2 years ago

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