Answer:
The percentage of the block contains 15% after 60 years.
Explanation:
Step 1: Formula for half-life time
To calculate the half-life time we will use the following formula:
At = A0 * 1/2 ^(x/t)
With At = the quantity after a time t
A0 = The quantity at time t = 0 (start)
x = time in this case = 60 years
t= half-life time = 22 years
Step 2: Calculate the percentage after 60 years
In this case: after 60 years the percentage will be
A0= 10 * 1/2 ^(60/22)
A0 = 1.5
A0 / At = 1.5 /10 = 0.15
0.15 *100% = 15 %
The percentage of the block contains 15% after 60 years.
Chemical bonds are formed or broken. This is true of a chemical change, but not a physical change. A physical change is usually something that you can see, such as changing of shape or form or staying the same. However, because you cannot visibly see chemical bonds being formed or broken and because this would affect the chemical composition, it is not a physical change.
They have a positive charge.
Answer:
16.8 L
Explanation:
From the question given above, the following data were obtained:
Number of mole of He = 0.750 mole
Volume of He =?
Recall:
1 mole of any gas occupy 22.4 L at STP. This also implies that 1 mole of He occupies 22.4 L at STP.
Finally, we shall determine the volume occupied by 0.750 mole of He. This can be obtained as follow:
1 mole of He occupied 22.4 L at STP.
Therefore, 0.750 mole of He will occupy = 0.750 × 22.4 = 16.8 L at STP.
Thus, 0.750 mole of He is equivalent to 16.8 L
Answer:
Explanation:
An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides.