Convection currents are flowing fluid that is moving because there is a temperature or density difference within the material. ... A temperature difference leads to an energy transfer from an area of higher energy to one of lower energy. Convection is a heat transfer process.
Answer:
<em><u>Question 1.</u></em><em> → </em>The amount remained is 15.625 g after 5 half-lives (30 hours).
<u><em>Question 2. </em></u><em>→ </em>mass % of water =41.4 %
<u><em>Question 3. </em></u><em>→ </em>C. 64 grams.
Explanation:
<em><u>Question 1. </u></em>
It is known that the decay of isotopes and radioactive material obeys first order kinetics.
Also, it is clear that in first order decay the half-life time is independent of the initial concentration.
Thus, 30 hours represent (30/6) 5 half-lives.
500 g →(first 1/2 life) 250 g →(second 1/2 life) 125 g →(third 1/2 life) 62.5 g →(fourth 1/2 life) 31.25 g →(fifth 1/2 life) 15.625 g
So, The amount remained is 15.625 g after 5 half-lives (30 hours).
<u><em>Question 2.</em></u>
- The formula of Copper (II) Fluoride tetra hydrate is CuF₂.4H₂O.
- the molar mass of Copper (II) Fluoride tetra hydrate is the sum of the atomic masses o each element.
- molar mass of 1 mol of CuF₂.4H₂O = 64 + 2*(19) + 8* (1) + 4*(16) = 174 g/mol.
- molar mass of 4 mol of H₂O = 8*(1) + 4*(16) = 72 g/mol
- 1 mol of Copper (II) Fluoride tetra hydrate → 4 mol H₂O
mass % of water = (mass of 4 mol of H₂O) / (mass of 1 mol of CuF₂.4H₂O ) *100 = (72 /174) *100 = 41.4 %
<em><u>Question 3. </u></em>
<u>Mass percentage</u> is defined as the mass of a solute divided by the total mass of the solution, multiplied by 100
- mass percent = ( mass of solute / mass of solution) *100
∴ 16 = ( mass of solute / 400 g) *100
mass of solute = (16* 400)/ 100 = 64 g.
So the right choice is C. 64 grams.
Answer:
- Energy of ultraviolet light is 19.878 10⁻¹⁸ J
- Energy of visible light is 3.9756 X 10⁻¹⁹ J
- Energy of infrared light is 19.878 X 10⁻³⁰ J
The answers indicate that wavelength is inversely proportional to the energy of light (photon)
Explanation:
Energy of photon E = hc/λ
where;
h is Planck's constant = 6.626 X 10⁻³⁴js
c is the speed of light (photon) = 3 X 10⁸ m/s
λ is the wavelength of the photon
⇒For ultraviolet ray, with wavelength λ = 1 x 10⁻⁸ m
E = (6.626 X 10⁻³⁴ X 3 X 10⁸)/ (1 x 10⁻⁸)
E = 19.878 10⁻¹⁸ J
⇒For Visible light, with wavelength λ = 5 x 10⁻⁷ m
E = (6.626 X 10⁻³⁴ X 3 X 10⁸)/ (5 x 10⁻⁷)
E = 3.9756 X 10⁻¹⁹ J
⇒For Infrared, with wavelength λ = 1 x 10⁴ m
E = (6.626 X 10⁻³⁴ X 3 X 10⁸)/ (1 x 10⁴)
E = 19.878 X 10⁻³⁰ J
From the result above, ultraviolet ray has the shortest wavelength, but it has the highest energy among other lights.
Also infrared has the highest wavelength but the least energy among other lights.
Hence, wavelength is inversely proportional to the energy of light (photon).
Answer:
Silicon
Explanation:
One of the most similar elements to carbon on periodic table is silicon. Several compounds formed between carbon or silicon and other elements are identical.
Carbon is an element found in life forms as a building block while silicon is a building block of machine components such as semiconductors
Silicon is an element that can sustain bonds, similar to carbon bonds and it is situated directly under carbon on the periodic table