Answer:
Considering the half-life of 10,000 years, after 20,000 years we will have a fourth of the remaining amount.
Explanation:
The half-time is the time a radioisotope takes to decay and lose half of its mass. Therefore, we can make the following scheme to know the amount remaining after a period of time:
Time_________________ Amount
t=0_____________________x
t=10,000 years____________x/2
t=20,000 years___________x/4
During the first 10,000 years the radioisotope lost half of its mass. After 10,000 years more (which means 2 half-lives), the remaining amount also lost half of its mass. Therefore, after 20,000 years, the we will have a fourth of the initial amount.
Answer:
Explanation:
to convert any value in miles per second to meters per second, just multiply the value in miles per second by the conversion factor 1609.344. So, 10095 miles per second times 1609.344 is equal to 1.625 × 107 meters per second.
True...............................
Answer:
Mass = 160 g
Explanation:
Given data:
Number of moles of sodium hydroxide = 4 mol
Mass of sodium hydroxide = ?
Solution:
Formula:
Mass = number of moles × molar mass of sodium hydroxide
Molar mass of sodium hydroxide = 40 g/mol
Mass = 4 mol × 40 g/mol
Mass = 160 g
The atomic number of an element is the same as the number of protons. As long as the atom is neutral, your electrons and protons will be the same number. To find neutrons, you subtract the atomic number from the mass number.
mass number - atomic number = number of neutrons
