Chemical change occur when two substances are combined and produces a new substance or decomposes into two or more substances which are entirely different from the original two substances.
There are three types of chemical changes. These are 1) Inorganic Changes, 2) Organic Changes, and 3) Biochemical Changes
Here are some examples of chemicsal changes.
If you combine Sodium and Water, chemical changes causes decomposition into Sodium Hydroxide and Hydrogen.
Sodium + Water ==> Sodium Hydroxide and Hydrogen
Na + H2O ====> NaOH and H
Another example of chemical change is:
Carbon Dioxide and Water will decompose into Sugar and Oxygen
Carbon Dioxide + Water ==> Sugar and Oxygen
CO2 + H2O ==> CnH2nOn (where n is between 3 and 7) and O
The quantity of substance remains after 850 years is 8.98g if the half life of radioactive radium is 1,599 years.
<h3>What is half life period? </h3>
The time taken by substance to reduce to its half of its initial concentration is called half life period.
We will use the half- life equation N(t)
N e^{(-0.693t) /t½}
Where,
N is the initial sample
t½ is the half life time period of the substance
t2 is the time in years.
N(t) is the reminder quantity after t years .
Given
N = 13g
t = 350 years
t½ = 1599 years
By substituting all the value, we get
N(t) = 13e^(0.693 × 50) / (1599)
= 13e^(- 0.368386)
= 13 × 0.691
= 8.98
Thus, we calculated that the quantity of substance remains after 850 years is 8.98g if the half life of radioactive radium is 1,599 years.
learn more about half life period:
brainly.com/question/20309144
#SPJ4
Answer:
B
Explanation:
The tendency of a liquid to convert to vapour increases smoothly with increasing temperature. Vapour pressure shows the tendency of a liquid to convert to vapour. Increase In vapour pressure shows an increased tendency to convert to vapour. The higher the temperature, the higher the vapour pressure.
Answer: 100.3 mmHg
Explanation:
Given that:
Volume of nitrogen gas V = 4.200 L
Temperature T = 21°C
Convert Celsius to Kelvin
(21°C + 273 = 294K)
Pressure P = ?
Number of moles of gas = 0.02300
Molar gas constant R is a constant with a value of 0.0821 atm L K-1 mol-1
Then, apply ideal gas equation
pV = nRT
p x 4.200L = 0.02300 moles x (0.0821 atm L K-1 mol-1 x 294K)
p x 4.200L = 0.555 atm L
p = 0.555 atm L / 4.200L
p = 0.132 atm
Now, convert pressure in atm to mmHg
If 1 atm = 760 mmHg
0.132 atm = (0.132 x 760) = 100.3 mmHg
Thus, 100.3 mmHg of pressure is required
