Answer: The mass of electrons is mostly ignored because electrons are extremely small compared to neutrons and protons.
Explanation: A proton is about 1,836 times the size of an electron.
On the periodic table, the atomic number for each element can be found. This number is found by measuring the weight of 6.02 x 10^23 atoms of the element in grams. Electrons aren't ignored when finding exact math, but for the sake of simplification high school teachers will generally have you only count the number of protons and neutrons when calculating the mass of atoms.
The number of bacteria is given by:
N(t) = N(o) x 2ⁿ
Where N(t) is the number after n hours have passed and N(o) is the original number which is 15.
The number grown in the 12th hour is the difference in the number after the 11th and the 12th hour. Thus:
15 x 2¹² - 15 x 2¹¹
= 30,720 bacteria
Answer:
D.
Explanation:
Translation:
A. make a barbecue
B. organize a picnic
C. swimming in the pool
D. to go skiing
Barbecue is usually a summer activity, so we eliminate that.
It would be too cold for a picnic!
It would be too cold to go swimming, and that's more of a summer thing!
Skiing is a snow activity, and since it is winter, it is likely to know.