The mass would be 28. The mass of an atom equals the number of neutrons and protons added together. In this case, they do not say the protons. But we must use our inside knowledge to know that the number of protons equals the number of electrons. Thus, your number of protons would be 13

Blank # 1 - keep safe distance from the burner
Blank # 2 - Place the equipments on the right place after use
Blank # 3 - perform experiments with proper lab equipment and safety tools
Blank # 4 - Don't break any test tube or lab equipment
(maybe it can be hazardous)
Answer:
0.03atm
Explanation:
Given parameters:
Total pressure = 780torr
Partial pressure of water vapor = 1.0atm
Unknown:
Partial pressure of radon = ?
Solution:
A sound knowledge of Dalton's law of partial pressure will help solve this problem.
The law states that "the total pressure of a mixture of gases is equal to the sum of the partial pressures of the constituent gases".
Mathematically;
P
= P
+ P
+ P
Since the total pressure is 780torr, convert this to atm;
760torr = 1 atm
780torr =
atm = 1.03atm
For this problem;
Total pressure = Partial pressure of radon + Partial pressure of water vapor
1.03 = Partial pressure of radon + 1.0
Partial pressure of radon = 1.03 - 1.00 = 0.03atm