Answer: the mass number of an element is equal to the number of protons plus the number of neutrons.
Answer:
precipitate , chemical
Explanation:
a precipitate is is an insoluble solid that forms when two solutions are combined and react chemically. The two clear colorless liquids is a chemical change because a different solid substance is formed
25.9 kJ/mol. (3 sig. fig. as in the heat capacity.)
<h3>Explanation</h3>
The process:
.
How many moles of this process?
Relative atomic mass from a modern periodic table:
- K: 39.098;
- N: 14.007;
- O: 15.999.
Molar mass of
:
.
Number of moles of the process = Number of moles of
dissolved:
.
What's the enthalpy change of this process?
for
. By convention, the enthalpy change
measures the energy change for each mole of a process.
.
The heat capacity is the least accurate number in these calculation. It comes with three significant figures. As a result, round the final result to three significant figures. However, make sure you keep at least one additional figure to minimize the risk of rounding errors during the calculation.