Answer:
The given atom is of Ca.
Explanation:
Given data:
Speed of atom = 1% of speed of light
De-broglie wavelength = 3.31×10⁻³ pm (3.31×10⁻³ / 10¹² = 3.31×10⁻¹⁵ m)
What is element = ?
Solution:
Formula:
m = h/λv
m = mass of particle
h = planks constant
v = speed of particle
λ = wavelength
Now we will put the values in formula.
m = h/λv
m = 6.63×10⁻³⁴kg. m².s⁻¹/3.31×10⁻¹⁵ m ×( 1/100)×3×10⁸ m/s
m = 6.63×10⁻³⁴kg. m².s⁻¹/ 0.099×10⁻⁷m²/s
m = 66.97×10⁻²⁷ Kg/atom
or
6.69×10⁻²⁶ Kg/atom
Now here we will use the Avogadro number.
The given problem will solve by using Avogadro number.
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
Now in given problem,
6.69×10⁻²⁶ Kg/atom × 6.022 × 10²³ atoms/ mol × 1000 g/ 1kg
40.3×10⁻³×10³g/mol
40.3 g/mol
So the given atom is of Ca.
Cr2(CO3)3 is Chromium (III) Carbonate or Chromic Carbonate.
It is composed of Chromium, Carbon, and Oxygen. Chromium has 2 atoms, Carbon has 3 atoms, and Oxygen has 9 atoms.
This compound is composed of 36.6% Chromium, 12.7% Carbon, and 50.7% Oxygen.
Buffer solution resist the change in pH upon addition of small amount of strong acid or strong base.
Buffer consists of weak acid as HF / and its conjugate base NaF
When strong acid as HCl is added to buffer, it respond with its conjugate base to convert the strong acid to weak acid like this:
HCl (S.A) + NaF → NaCl + HF (W.A)
moles of HF we already have = M * V(in liters)
= 0.0955 M * 0.033 L = 3.15 x 10⁻³ mole
moles of HCl added = 8.00 x 10⁻⁵ mole
one mole HCl reacts with 1 mole NaF to give 1 mole HF
so the amount added to HF = 8.00 x 10⁻⁵
Total moles of HF present = (3.15 x 10⁻³) + (8.00 x 10⁻⁵) = 3.23 x 10⁻³ mole
Professor of Physics Carlo Rubbia
