Molality can be expressed by moles of solute over
kilograms of solvent. The question asks the molality of 0.25m NaCl. 0.25m NaCl
is equal to 0.25 moles of NaCl over 1 kg of water.
Answer : The age of the artifact is,
Explanation :
Half-life = 5715 years
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the time taken to decay.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant
t = time taken by sample = ?
a = initial activity of the reactant = 58.2 counts per minute
a - x = activity left after decay process = 42.8 counts per minute
Now put all the given values in above equation, we get
Therefore, the age of the artifact is,
Answer:
1. final pressure = 0.259atm
2. 196.84mmHg
Explanation:
Using Boyle's law of equation
P1V1 = P2V2
Where;
P1 = initial pressure (atm)
P2 = final pressure (atm)
V1 = initial volume (mL)
V2 = final volume (mL)
According to the information given in this question:
V1 = 105mL
V2 = 352mL
P1 = 0.871atm
P2 = ?
Using P1V1 = P2V2
P2 = P1V1/V2
P2 = 0.871 × 105/352
P2 = 91.455/352
P2 = 0.2598
P2 = 0.259atm
To convert 0.259atm of the gas into mmHg, we multiply the value in atm by 760.
Hence, 0.259 × 760
= 196.84mmHg