Answer:
half-life = 3.8 days
total time of decay = 15.2 days
initial amount = 100. g
number of half-lives past: 15.2/3.8 = 4 half-lives
4 half-lives = 1/16 remains
100. g x 1/16 = 6.25 g
The equation for energy of a photon is E=hv where v equals frequency and h equals the Planck constant (6.626X10^-34). So since you've been given frequency you can just plug in frequency to find the total energy in joules.
E=(3.55X10^17)(6.626X10^-34)
E=2.35223X10^-16
Not sure how many significant figures you needed. Hope this helped.
Answer:
6.022 x 10²³; it is a conversion factor between moles and number of particles
Explanation:
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
1.008 g of hydrogen = 1 mole of hydrogen = 6.022 × 10²³ atoms of hydrogen
238 g of uranium = 1 mole of uranium = 6.022 × 10²³ atoms of uranium
By taking ions:
62 g of NO⁻₃ = 1 mole of NO⁻₃ = 6.022 × 10²³ ions of NO⁻₃
96 g of SO₄²⁻ = 1 mole of SO₄²⁻ = 6.022 × 10²³ ions of SO₄²⁻
Answer:
they must have same atomic number and different atomic mass
