Answer:
m = 31.284 grams
Explanation:
Given that,
The dimension of a magnesium block is 2.00 cm x 3.00 cm x 3.00 cm.
The density of magnesium is, d = 1.738 g/cm³
We need to find the mass of the magnesium block. We know that the density of an object is given by its mass per unit its volume. So,
So, the mass of the block is 31.284 grams.
Answer:
The electrochemical equivalent of copper, Cu, is 3.29015544 × 10⁻⁷ g/C
Explanation:
The given parameters are;
The element for which the electrochemical equivalent is sought = Copper
The atomic mass of copper = 63.5
The electrochemical equivalent, 'Z', of an element or a substance is the mass, 'm', of the element or substance deposited by one coulomb of electricity, which is equivalent to a 1 ampere current flowing for a period of 1 second
Mathematically, we have;
m = Z·I·t = Z·Q
We have;
Cu²⁺ (aq) + 2·e⁻ → Cu
Therefore, one mole of Cu, is deposited by 2 moles of electrons
The charge carried one mole of electrons = 1 Faraday = 96500 C
∴ The charge carried two moles of electrons, Q = 2 × 96500 C = 193,000 C
Given that the mass of an atom of Cu = 63.5 a.m.u., the mass of one mole of Cu, m = 63.5 g
∴ Z = 3.29015544 × 10⁻⁴ g/C = 3.29015544 × 10⁻⁷ g/C
The electrochemical equivalent of copper, Cu, is Z = 3.29015544 × 10⁻⁷ g/C
<u>Answer:</u> The longest wavelength of light is 656.5 nm
<u>Explanation:</u>
For the longest wavelength, the transition should be from n to n+1, where: n = lower energy level
To calculate the wavelength of light, we use Rydberg's Equation:
Where,
= Wavelength of radiation
= Rydberg's Constant =
= Higher energy level =
= Lower energy level = 2 (Balmer series)
Putting the values in above equation, we get:
Converting this into nanometers, we use the conversion factor:
So,
Hence, the longest wavelength of light is 656.5 nm