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Jobisdone [24]
3 years ago
11

Technetium has a half-life of six hours. If you obtain 100g of a pure technetium sample, after 18 hours how much of the pure sub

stance will be remaining?
Chemistry
1 answer:
Butoxors [25]3 years ago
5 0

Answer: 12.5 grams.

Explanation:

You can find the amount of pure substance remaining by using the half-life formula:

Q_{1}=Q(\frac{1}{2})^{\frac{t}{t2} }

Where t is the amount of time, and t2 is the half life of the substance.

Substituting our values for the variables, we get this equation:

Q_{1} = 100(\frac{1}{2})^3\\\\Q_{1} = 100(\frac{1}{8})\\\\Q_{1} = 12.5

After 18 hours, there will be 12.5 grams of the substance remaining.

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How many isomers does propane have?<br> 01<br> 02<br> 03<br> 05
Irina18 [472]

Answer:

A.) 1

Explanation:

Propane only exists in one conformation. It does not have enough carbons to form branches, and there are only hydrogens attached to each carbon. Furthermore, there is no way to twist the carbon or change its orientation (ex. cis- and trans-) to result in a different structure of propane. There is no other way to represent the molecule without drawing a different molecule.

5 0
1 year ago
PLS HELP THIS IS TIMED
hammer [34]

Answer:

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Explanation:

4 0
2 years ago
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P4O10 -&gt; 4P+5O2 How many moles of phosphorus would be produced if 5.3 mol of P4O10 reacted?
viktelen [127]

Answer:

21.2 moles.

Explanation:

Hello!

In this case, for the given chemical reaction, we can see there is a 1:4 mole ratio between tetraphosphorous decaoxide and phosphorous; therefore, the following proportional factor provides the requested moles of phodphorous:

n_P=5.3molP_4O_{10} *\frac{4molP}{1molP_4O_{10}} \\\\n_P=21.2molP

Best regards!

5 0
3 years ago
You wish to prepare an HC2H3O2 buffer with a pH of 4.24. If the pKa of is 4.74, what ratio of C2H3O2 /HC2H3O2 must you use?
LenaWriter [7]

To solve this problem, we can use the Henderson-Hasselbalch Equation which relates the pH to the measure of acidity pKa. The equation is given as:<span>

<span>pH = pKa + log ([base]/[acid])                ---> 1</span></span>

Where,

[base] = concentration of C2H3O2 in molarity or moles

<span>[acid] = concentration of  HC2H3O2 in molarity or moles</span>

 

For the sake of easy calculation, let us assume that:

[base] = 1

[acid] = x

<span>
Therefore using equation 1,
4.24 = 4.74 + log (1 / x) 

<span>log (1 / x) = - 0.5

1 / x = 0.6065 </span></span>

x = 1.65<span>

The required ratio of C2H3O2 /HC2H3O2 <span>is 1:1.65 or 3:5. </span></span>
3 0
3 years ago
If a shell can hold a maximum of 32 electrons, what is the value of n?
olga2289 [7]
<span>Begin by classifying which energy level, and indirectly principal quantum number, n, resembles to the N shell. no. of orbitals =n2 In your case, the fourth energy level will contain n=4⇒no. of orbitals= 4^2=16 The number of subshells is given by the principal quantum number. no. of subshells=n In your case, the fourth energy level will have no. of subshells = 4 this is the answer to check: the fourth energy shell will can hold a thoroughgoing of no. of electrons=2⋅42=32 e−</span>
4 0
3 years ago
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