The masses can be found by substractions:
- Mass of CaSO₄.H2O (hydrate):
16.05 g - 13.56 g = 2.49 g
15.07 g - 13.56 g = 1.51 g
- The mass of water is equal to the difference between the mass of the hydrate and the mass of the anhydrate:
2.49 g - 1.51 g = 0.98 g
- The percent of water is found by the formula:
massWater ÷ massHydrate * 100%
0.98 g ÷ 2.49 g * 100% = 39.36%
- The mole of water is calculated using water's molecular weight (18g/mol):
0.98 g ÷ 18 g/mol = 0.054 mol water
- A similar procedure is made for the mole of salt (CaSO₄ = 136.14 g/mol)
1.51 g ÷ 136.14 g/mol = 0.011 mol CaSO₄
- The ratio of mole of water to mole of anhydrate is:
0.054 mol water / 0.011 mol CaSO₄ = 0.49
In other words the molecular formula for the hydrate salt is CaSO₄·0.5H₂O
Answer:
9. 8.2x10¹⁴ Hz
Explanation:
Wavelength λ = 366 nm
Formula: Frequency = C / λ
To find the wavelength in m,
1 nm = 1.0x10⁻⁹ m
So, 366 nm = ?
= 3.66x10⁻⁷ m
Frequency = 3.0x10⁸m.s-1 / 3.66x10⁻⁷ m
= 8.2x10¹⁴ s-1
First, we need to calculate the principal quantum number n for this electron, using the equation:
E = (-13.60 eV) / (n x n)
where E is the energy that is used to bound the electron (here, E = - 0.544 eV).
- 0.544 eV = (-13.60 eV) / (n x n)
n x n = (- 13.60 eV) / (- 0.544 eV)
n x n = 25
n = 5
The orbital radius that is equal to the radius of a hydrogen atom is calculated using the equation:
r = 0.053 nm x n x n
r = 0.053 nm x 5 x 5
r = 0.053 nm x 25
r = 1.325 nm
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➷ For scientific uses, the main key property is that gold is unreactive. Gold is naturally occurring and found in nature. It is highly unreactive. This is also a beneficial quality for industrial uses such as making jewelry. Gold has tarnish resistance and takes a lot longer to dull in color than many other metals. Also, Gold is highly ductile meaning it can be drawn into thin wires to create detailed and delicate jewelry.
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➶ Hope This Helps You!
➶ Good Luck (:
➶ Have A Great Day ^-^
↬ ʜᴀɴɴᴀʜ ♡
