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jok3333 [9.3K]
2 years ago
7

What percentage of a substance remains after 7 half-lives have passed?

Chemistry
1 answer:
Mila [183]2 years ago
5 0

Answer:

Not really sure, buts its either B or C.

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A standard soft drink can has a volume of 0.355 L. An empty can is sealed while
beks73 [17]

Answer:

0.35 atm

Explanation:

To solve this problem, we use Boyle's Law: P_1V_1=P_2V_2 , where P is the pressure and V is the volume.

Here, V_1 = 0.355 L, P_1 = 1.0 atm, and V_2 = 0.125 L. So, just plug these values into the equation:

(1.0) * (0.355) = P_2 * (0.125)  ⇒  P_2 ≈ 0.35 atm

Thus, the pressure is 0.35 atm.

Hope this helps!

8 0
3 years ago
What percentage of the mass of hydrofluoric acid (HF) is contributed by hydrogen?
Morgarella [4.7K]

This problem is asking for the percent by mass of hydrogen in hydrofluoric acid. At the end, the answer turns out to be D. 5%​ as shown below:

<h3>Percent compositions:</h3>

In chemistry, percent compositions are used for us to know the relative amount of a specific element in a compound. In order to do so for hydrogen, we use the following formula, which can also be applied to any other element in a given compound:

\% H=\frac{m_H*1}{M_{HF}}*100\%

Where m_H stands for the atomic mass of hydrogen and M_{HF} for the molar mass of hydrofluoric acid. In such a way, we plug in the atomic masses of hydrogen (1.01 g/mol) and fluorine (19.0 g/mol) to obtain:

\% H=\frac{1.01g/mol*1}{1.01g/mol+19.0g/mol}*100\%\\\\\% H=5\%

Learn more about percent compositions: brainly.com/question/12247957

5 0
2 years ago
Isaac Newton’s investigations of gravity explained which truth?
umka2103 [35]
<span>C. Gravity acts on all objects in the universe.
think about Newtons Laws of Motion</span>
4 0
3 years ago
Read 2 more answers
What is the iupac name of the following compound? <br><br> 2,2-dimethyl-4-ethylheptane
Lady bird [3.3K]

Answer:

The IUPAC name of the compound has already been given which is 2,2-dimethyl-4-ethylheptane.

Explanation:

The IUPAC (International Union of Pure and Applied Chemistry) is an authority in chemistry that provides a guideline and standardized methods in the naming of compounds formed from the periodic table.

In order the give an IUPAC name to a compound, certain steps needs to be followed, these includes:

--> Identify the functional group in the compound as this will form the suffix. For example if the functional group is an alkane the suffix will be -ane.

--> Identify the longest carbon chain (it may not be a straight chain) that contains the functional group. This forms the prefix. Example: if the longest carbon chain is 7 carbon atoms then the prefix will be hept-

--> All the carbons of the longest chain should be numbered

--> Identify branched groups on the chain and name them according to the number of carbon atoms. They usually end with -yl.

--> Finally, combine the elements of the name is a single word.

The structural formula of the IUPAC compound can be found in the attached file for a better understanding. The branched groups are circled.

4 0
3 years ago
The teacher tells your group to make a stock solution of sodium chloride, and then diluting it to
sergejj [24]

The idea here is that you need to figure out how many moles of magnesium chloride,

MgCl

2

, you need to have in the target solution, then use this value to determine what volume of the stock solution would contain this many moles.

As you know, molarity is defined as the number of moles of solute, which in your case is magnesium chloride, divided by liters of solution.

c

=

n

V

So, how many moles of magnesium chloride must be present in the target solution?

c

=

n

V

⇒

n

=

c

⋅

V

n

=

0.158 M

⋅

250.0

⋅

10

−

3

L

=

0.0395 moles MgCl

2

Now determine what volume of the target solution would contain this many moles of magnesium chloride

c

=

n

V

⇒

V

=

n

c

V

=

0.0395

moles

3.15

moles

L

=

0.01254 L

Rounded to three sig figs and expressed in mililiters, the volume will be

V

=

12.5 mL

So, to prepare your target solution, use a

12.5-mL

sample of the stock solution and add enough water to make the volume of the total solution equal to

250.0 mL

.

This is equivalent to diluting the

12.5-mL

sample of the stock solution by a dilution factor of

20

.

3 0
2 years ago
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