The substances that are formed by a chemical change are called the product.
While the state of matter in which a material has a definite volume and a definite shape is the solid.
In a chemical reaction, the reactant on the left hand side undergoes a chemical change and gives product.
While in a solid state, a material has a definite volume and a definite shape is the solid.
It is clearly (a) is Einstein's equation
Answer:
The answer to your question is the original dose of Ba-142 was 1184 μg
Explanation:
Data
Total time = 1.25 hours
The Final amount of Ba = 9.25 μg
The Half-life of Ba = 10.6 minutes
Process
1.- Convert total time to minutes
1 h ----------------- 60 min
1.25 h ------------ x
x = 75 min
2.- Draw a table of this process
Final amount of Ba Time
9.25 75 min
18.5 64.4 min
37 53.8 min
74 43.2 min
148 32.6 min
296 22 min
592 11.4 min
1184 0.8 min
You can split the process in two parts:
1) heating the liquid water from 10.1 °C to 25.0 °C , and
2) vaporization of liquid water at constant temperature of 25.0 °C.
For the first part, you use the formula ΔH = m*Cs*ΔT
ΔH = 30.1g * 4.18 j/(g°C)*(25.0°C - 10.1°C) = 1,874 J
For the second part, you use the formula ΔH = n*ΔHvap
Where n is the number of moles, which is calculated using the mass and the molar mass of the water:
n = mass / [molar mass] = 30.1 g / 18.0 g/mol = 1.67 mol
=> ΔH = 1.67 mol * 44,000 J / mol = 73,480 J
3) The enthalpy change of the process is the sum of both changes:
ΔH total = 1,874 J + 73,480 J = 75,354 J
Answer: 75,354 J
