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 :)
The specific heat is the amount of heat per unit mass required to raise the temperature to 1 degree Celsius. (This is from google)
Answer :
121.5 <span>
μCi
Explanation : We have Ce-141 half life given as 32.5 days so if the activity is 3.8 </span><span>μci after 162.5 days of time elapsed we have to find the initial activity.
We can use this formula;
</span>
3.8 /
=
((0.693 X 162.5 ) / 32.5) = 121.5
<span>
On solving we get, The initial activity as 121.5 </span>μci
Answer:
P = 27.9 atm
Explanation:
Given data:
Mass of CO₂ = 25 g
Temperature = 25°C (25+273.15 K = 298.15 K)
Volume of gas = 0.50 L
Pressure of gas = ?
Solution:
Firs of all we will calculate the number of moles of gas,
Number of moles = mass/molar mass
Number of moles = 25 g/ 44 g/mol
Number of moles = 0.57 mol
Pressure of gas :
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
P × 0.50 L = 0.57 mol × 0.0821 atm.L/ mol.K × 298.15 K
P = 13.95 atm.L/ 0.50 L
P = 27.9 atm
