The alpha particle is the helium nucleus.
The mass of helium nucleus (⁴₂He) is 4u.
The mass of radioactive atom decreases by 4u. Look at the reaction below:
²²³₈₈Ra ---> ⁴₂He + ²¹⁹₈₆Rn
Answer:
C
Explanation:
You mix different thing together to make a new thing.
The correct answer is carbon dioxide and water vapor
These negative gasses get modified and then remain in the atmosphere without the possibility of leaving, which is why the greenhouse effect occurs.
Percent error is the difference between the measured and known value, divided by the known value, multiplied by 100%.
So first, we take our measured value, .299 cm, minus our known value, .225 cm.
.299 cm - .225 cm=.004 cm
Next, we divide that by our known value

Finally, multiply your answer by 100
.0177777778 x 100= 1.77777778 %
Round to three significant figures, and you're done.
=1.78 % error
If you meant the word silicon then yes, silicon is a semiconductor and its ability to conduct gets better as the temp. rises