Answer:
this lesson is the third in a three-part series about the nucleus, isotopes, and radioactive decay. The first lesson, Isotopes of Pennies, deals with isotopes and atomic mass. The second lesson, Radioactive Decay: A Sweet Simulation of Half-life, introduces the idea of half-life.
By the end of the 8th grade, students should know that all matter is made up of atoms, which are far too small to see directly through a microscope. They should also understand that the atoms of any element are alike but are different from atoms of other elements. Atoms may stick together in well-defined molecules or they could be packed together in large arrays.
For students, understanding the general architecture of the atom and the roles played by the main constituents of the atom in determining the properties of materials now becomes relevant. Having learned earlier that all the atoms of an element are identical and are different from those of all other elements, students now come up against the idea that, on the contrary, atoms of the same element can differ in important ways. (Benchmarks for Science Literacy, p. 79.)
In this lesson, students will be asked to consider the case of when Frosty the Snowman met his demise (began to melt). The exercise they will go through of working backwards from measurements to age should help them understand how scientists use carbon dating to try to determine the age of fossils and other materials. To be able to do this lesson and understand the idea of half-life, students should understand ratios and the multiplication of fractions, and be somewhat comfortable with probability
Explanation:
The element that she discovered was radium.
Answer:
ν = 5,765x10¹⁴ Hz
λ = 520 nm
230,0 kJ/mole
Explanation:
To convert energy yo frequency you need to use:
E = hν
Where E is energy (3,820x10⁻¹⁹ J)
h is Planck's constant (6,626x10⁻³⁴ Js)
And ν is frequency, replacing ν = 5,765x10¹⁴ s⁻¹ ≡ 5,765x10¹⁴ Hz
To convert frequency to wavelength:
c = λν
Where s is speed of light (2,998x10⁸ ms⁻¹)
ν is frequency (5,765x10¹⁴ s⁻¹)
And λ is wavelength, replacing: λ = 5,200x10⁻⁷ ≡ 520 nm
If 1 photon produce 3,820x10⁻¹⁹ J, in mole of photons produce:
3,820x10⁻¹⁹ J ×
= 230040 J/mole ≡ 230,0 kJ/mole
I hope it helps!
Molar mass NH3 = 17.031 g/mol
1 mole NH3 -------------- 17.031 g
?? moles NH3 ---------- 346 g
346 x 1 / 17.031
=> 20.31 moles of NH3
To determine the mass, you need to know the molecular weight of the c8h10n4o2 . The molecular weight of <span>c8h10n4o2 would be: 8*12 + 10*1 + 4*14 + 2*16= 194g/mol.
To convert the number of molecules into moles, you need to divide it with 6.02 * 10^23. The calculation of the mass of </span>c8h10n4o2 would be:
(7.20×10^20 molecules) /(6.02 * 10^23 molecule/mol) * 194g/mol= 232 * 10^-3 grams= 0.232 grams
