There are 8.61 × 10²⁰ atoms in 0.290 g P₂O₅.
Step 1. Convert <em>grams of P₂O₅ to moles of P₂O₅</em>.

Step 2. Convert <em>moles of P₂O₅ to molecules of P₂O₅</em>.


Step 3. Convert <em>molecules of P₂O₅ to atoms</em>.
There are seven atoms in 1 mol P₂O₅.
∴ 
We need an equation that would relate the concentration of the original solution to that of the desired solution. To solve this we use the equation expressed as follows,
M1V1 = M2V2
where M1 is the concentration
of the stock solution, V1 is the volume of the stock solution, M2 is the
concentration of the new solution and V2 is its volume.
M1V1 = M2V2
0.266 M x V1 = 0.075 M x 150 mL
V1 = 42.29 mL
Therefore, we need about 42.29 mL of the 0.266 M of lithium nitrate solution to make 150.0 mL of the 0.075 M lithium nitrate solution.
Answer :
(a) The density of mercury is, 13.6 g/ml
(b) The mass of 120.0 ml of mercury is, 1632 grams
Explanation :
(a) Now we have to calculate the density of mercury.
<u>Given :</u>
Volume of mercury = 25.0 ml
Mass of mercury = 340.0 g
Formula used :


Therefore, the density of mercury is, 13.6 g/ml
(b) Now we have to calculate the mass of 120.0 ml of mercury.
As, 25.0 ml of mercury has mass = 340.0 g
So, 120.0 ml of mercury has mass = 
Therefore, the mass of 120.0 ml of mercury is, 1632 grams
Answer:
Its in the Explanation
Explanation:
Here's what I got.
Aluminium-27 is an isotope of aluminium characterized by the fact that is has a mass number equal to
27
.
Now, an atom's mass number tells you the total number of protons and of neutrons that atom has in its nucleus. Since you're dealing with an isotope of aluminum, it follows that this atom must have the exact same number of protons in its nucleus.
The number of protons an atom has in its nucleus is given by the atomic number. A quick looks in the periodic table will show that aluminum has an atomic number equal to
13
.
This means that any atom that is an isotope of aluminum will have
13
protons in its nucleus.
Since you're dealing with a neutral atom, the number of electrons that surround the nucleus must be equal to the number of protons found in the nucleus.
Therefore, the aluminium-27 isotope will have
13
electrons surrounding its nucleus.
Finally, use the known mass number to determine how many neutrons you have
mass number
=
no. of protons
+
no. of neutrons
no. of neutrons
=
27
−
13
=
14
Your welcome :)