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.
We are given that 1 teaspoon is equivalent to 5 mL,
therefore 0.75 teaspoon is:
0.75 teaspoon * (5 mL / 1 teaspoon) = 3.75 mL
So the mass is density times volume:
mass = (12.5 mg/5 ml) * 3.75 mL
<span>mass = 9.375 mg</span>
Answer: It's D
Explanation:
I just did this question and i picked C but it's actually D
<u>Answer:</u> The ion that is expected to have a larger radius than the corresponding atom is chlorine.
<u>Explanation:</u>
There are two types of ions:
- <u>Cations:</u> They are formed when an atom looses its valence electrons. They are positive ions.
- <u>Anions:</u> They are formed when an atom gain electrons in its outermost shell. They are negative ions.
For positive ions, the removal of electron increases the nuclear charge for an outermost electron because the outermost electrons are more strongly attracted by the nucleus. So, the effective nuclear charge increases for cations and thus, the size of the cation will be smaller than that of the corresponding atom.
For negative ions, the addition of electron decreases the nuclear charge for an outermost electron because the outermost electrons are less strongly attracted by the nucleus. So, the effective nuclear charge decreases for anions and thus, the size of the anion will be larger than that of the corresponding atom.
For the given options:
<u>Option a:</u> Chlorine
Chlorine gains 1 electron and form 
ion
<u>Option b:</u> Sodium
Sodium looses 1 electron and form 
ion
<u>Option c:</u> Copper
Copper looses 2 electrons and form 
ion
<u>Option d:</u> Strontium
Strontium looses 2 electrons and form 
ion
Hence, the ion that is expected to have a larger radius than the corresponding atom is chlorine.
