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2 years ago

The half-life of phosphorous-32 is 14.28 days. How many days are required for 4.68 g to remain if you start with 74.88

Chemistry

1 answer:

Anastasy [175]2 years ago

4 0

57.167days will be required for 4.68g to remain

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did this and got 8.3 x 10-5 can someone help me figure out how i got this wrong since these are the only answer choices?

Bezzdna [24]

It is b i think bc it looks like it would be it and my tudor helped me

4 0

2 years ago

Given that the molar mass of NaCl is 58.44 g/mol, what is the molarity of a solution that contains 87.75 g of NaCl in 500. mL of

Stells [14]

Given information:

Mass of NaCl (m) = 87.75 g

Volume of solution (V) = 500 ml = 0.5 L

Molar mass of NaCl (M) = 58.44 g/mol

To determine:

The molarity of NaCl solution

Explanation:

Molarity is defined as the number of moles of solute(n) dissolved per liter of solution (V)

i.e. M = moles of solute/liters of solution = n/V

Moles of solute (n) = mass of solute (m)/molar mass (M)

moles of NaCl = 87.75 g/58.55 g.mol-1 = 1.499 moles

Therefore,

Molarity of NaCl = 1.499 moles/0.5 L = 2.998 moles/lit ≅ 3 M

Ans: (D)

4 0

3 years ago

Read 2 more answers

The heat of fusion AH, of ethyl acetate (C4H802) is 10.5 kinol. Calculate the change in entropy as when 398. g of ethy, acetate

Hitman42 [59]

Answer: The entropy change of the ethyl acetate is 133. J/K

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of ethyl acetate = 398 g

Molar mass of ethyl acetate = 88.11 g/mol

Putting values in above equation, we get:

$\text{Moles of ethyl acetate}=\frac{398g}{88.11g/mol}=4.52mol$

To calculate the entropy change for different phase at same temperature, we use the equation:

$\Delta S=n\times \frac{\Delta H_{fusion}}{T}$

where,

$\Delta S$ = Entropy change = ?

n = moles of ethyl acetate = 4.52 moles

$\Delta H_{fusion}$ = enthalpy of fusion = 10.5 kJ/mol = 10500 J/mol (Conversion factor: 1 kJ = 1000 J)

T = temperature of the system = $84.0^oC=[84+273]K=357K$

Putting values in above equation, we get:

$\Delta S=\frac{4.52mol\times 10500J/mol}{357K}\\\\\Delta S=132.9J/K$

Hence, the entropy change of the ethyl acetate is 133. J/K

7 0

2 years ago

Select the correct answer.

vitfil [10]

Answer:

The answer is B

Explanation:

6 0

3 years ago

Read 2 more answers

If the farmer had weighed out 32.0 pounds of chicken eggs rather than kilograms what mass of quail eggs would he need to weigh o

Ira Lisetskai [31]

To have 35 pounds of quail eggs, he would need 14.5 kilograms
1 pound= .45 pounds

8 0

2 years ago