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2 years ago

8

A lead mass is heated and placed in a foam cup caloriemeter containing 40.0mL of water at 17.0 C. The water reaches a temperatur

e of 20.0 C. How many joules of heat were released by the lead?

1 answer:

Mrrafil [7]2 years ago

8 0

the Answer is 502 Joules

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PLEASE ANSWER NEED BY MIDNIGHT TONIGHT!!!!!!

maksim [4K]

The equation for carbon-14 emission by Radium-223 nuclei is given below:

$^{223}_{88}Ra \rightarrow\: ^{209}_{82}Pb + \:^{14}_{6}C$

<h3>What is radioactivity?</h3>

Radioactivity is the spontaneous decay of a substance with emission of radiation.

The equation for carbon-14 emission by Radium-223 nuclei is given below:

$^{223}_{88}Ra \rightarrow\: ^{209}_{82}Pb + \:^{14}_{6}C$

In conclusion, the emission of carbon-14 by Radium-223 nuclei produces Lead-209 nuclei.

Learn more about radioactivity at: brainly.com/question/3603596

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5 0

1 year ago

What is the volume of 4.78g of O2 gas at STP?

My name is Ann [436]

Answer:

Explanation:

The trick here is to realize that if you know the volume of a gas at STP, you can use the fact that

1

mole of any ideal gas occupies

22.7 L

under STP conditions to calculate how many moles of gas you have in your sample.

Under STP conditions:

1 mole of an ideal gas = 22.7 L

−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

In your case, you know that your sample of gas occupies

2.28 L

under STP conditions, which are currently defined as a pressure of

100 kPa

and a temperature of

0

∘

C

.

This means that your sample will contain

2.28

L

⋅

molar volume of a gas at STP



1 mole gas

22.7

L

=

0.10044 moles gas

Now, the molar mass of the gas is the mass of exactly

1

mole of the gas. In your case, you know that you get

3.78 g

for every

0.10044

moles, which means that you have

1

mole

⋅

3.78 g

0.10044

moles

=

37.6 g

Since this is the mass of

1

mole of gas, you can say that the molar mass of the gas is

molar mass = 37.6 g mol

−

1

−−−−−−−−−−−−−−−−−−−−−−−

8 0

2 years ago

Read 2 more answers

Understanding chemistry is important for all citizens, particularly people who wish to become political leaders one day

V125BC [204]

Yes and no because it's important for a citizen to have a grasp on chemistry but you do not need it to be a politician

4 0

3 years ago

Read 2 more answers

Compare 1 mole of H2, 1 mole of O2, and 1 mole of F2. (a) Which has the largest number of molecules? Explain why. (b) Which has

AURORKA [14]

<u>a) Answer: </u>

<em>Number of molecules in 1 mole</em>

<u>Explanation:</u>

a) Whether we take any of the substance among all three of the given substances they will have the same number of molecules in 1 mole of the substance is considered and the value for this will be $6.023 x 10^23$

<u>b) Answer: </u>

<em>In the given question </em><em>mass of the substance</em><em> which is </em><em>greatest</em><em> is asked for </em><em>one mole</em><em> and we also know that </em><em>mass of one mole is given by molar mass. </em>

<u>Explanation:</u>

b) It is known that $31.98g/mol$ is the molar mass for oxygen which is greater than that of hydrogen while fluorine has a molar mass of $38.0 g/mol$ which on comparison shows that, it is the highest amongst all three.

3 0

3 years ago

P4O10(s) = -3110 kJ/mol H2O(l) = -286 kJ/mol H3PO4(s) = -1279 kJ/mol Calculate the change in enthalpy for the following process:

mash [69]

Answer:

-290KJ/mol

Explanation:

ΔHrxn = ΔHproduct - ΔHreactant

ΔHrxn= 4ΔHH3PO4 - {6ΔHH2O + ΔHP4O10}

ΔHrxn = 4(-1279) - [6(-286) - 3110]

= -5116 -(-1716-3110)

= -5116-(-4826)

= -5116 + 4826 = -290KJ/mol

6 0

2 years ago