<u>Answer:</u> The mass defect for the formation of phosphorus-31 is 0.27399
<u>Explanation:</u>
Mass defect is defined as the difference in the mass of an isotope and its mass number.
The equation used to calculate mass defect follows:
![\Delta m=[(n_p\times m_p)+(n_n\times m_n)]-M](https://tex.z-dn.net/?f=%5CDelta%20m%3D%5B%28n_p%5Ctimes%20m_p%29%2B%28n_n%5Ctimes%20m_n%29%5D-M)
where,
= number of protons
= mass of one proton
= number of neutrons
= mass of one neutron
M = mass number of element
We are given:
An isotope of phosphorus which is 
Number of protons = atomic number = 15
Number of neutrons = Mass number - atomic number = 31 - 15 = 16
Mass of proton = 1.00728 amu
Mass of neutron = 1.00866 amu
Mass number of phosphorus = 30.973765 amu
Putting values in above equation, we get:
![\Delta m=[(15\times 1.00728)+(16\times 1.00866)]-30.973765\\\\\Delta m=0.27399](https://tex.z-dn.net/?f=%5CDelta%20m%3D%5B%2815%5Ctimes%201.00728%29%2B%2816%5Ctimes%201.00866%29%5D-30.973765%5C%5C%5C%5C%5CDelta%20m%3D0.27399)
Hence, the mass defect for the formation of phosphorus-31 is 0.27399
Using accurate measurements, using pure chemicals and performing the reaction under the most ideal conditions is important to get a valuable percent yield.
<h3>How we calculate the percent yield?</h3>
Percent yield of any chemical reaction is define as the ratios of the actual yield to the theoretical yield of the product and multiply by the 100.
To get the high percent yield or actual yield of any reaction, we have to perform the reaction under ideal condition because if we not use the standard condition then we get the low rate of reaction. Reactants should be present in the pure form as impurity make unwanted products and reduce the productivity of main product and accurate amount of reactants also important for the spontaneous reaction.
Hence, options (a), (b) & (c) are correct.
To know more about percent yield, visit the below link:
brainly.com/question/8638404
Answer:
3.711 L
Explanation:
The formula you need to use is the following:

3.4L / 298 K = V2 / 273 K
V2 = 3.711 L
Answer:

Explanation:
Molarity is a measure of concentration in moles per liter.

The molarity of the solution is 1.2 M NaNO₃ or 1.2 moles NaNO₃ per liter. There are 0.25 liters of the solution. The moles of solute are unknown, so we can use x.
- molarity= 1.2 mol NaNO₃/L
- liters of solution=0.25 L
- moles of solute =x

We are solving for x, so we must isolate the variable, x. It is being divided by 0.25 liters. The inverse of division is multiplication, so we multiply both sides by 0.25 L.


The units of liters cancel, so we are left with the units moles of sodium nitrate.


There are 0.3 moles of sodium nitrate.