8.60*10^23 / 6.02*10^23 (# of atoms in one mole) = 1.43 moles
1.43*26.98 (atomic mass of Al. In other words, this is how much one mole of Al atoms weighs in grams) =
38.54g
38.54g is how much this piece of foil would weigh.
Answer:
Explanation:
Every A will be paired with a T, and every C with a G and vice versa (T to A, and G to C)
So the first letters in the sequence are ATGGG. So the pair will be TACCC.
The given chemical reaction is:
Δ∑BE(reactants)-∑BE(products)
= {(941 kJ/mol) + (3 * 242 kJ/mol)} -[{2*(3*200 kJ/mol)}]
= 467 kJ/mol
Calculating the change in heat when 85.3 g chlorine reacts in the above reaction:
Moles of chlorine =
= 1.20 mol
Heat change when 1.20 mol chlorine reacts
=
Answer:
(a)
(b)
(c)
(d)
Explanation:
Hello,
In this case, given the solubility of each salt, we can compute their molar solubilities by using the molar masses. Afterwards, by using the mole ratio between ions, we can compute the concentration of each dissolved and therefore the solubility product:
(a)
In such a way, as barium and selenate ions are in 1:1 molar ratio, they have the same concentration, for which the solubility product turns out:
(B)
In such a way, as barium and bromate ions are in 1:2 molar ratio, bromate ions have twice the concentration of barium ions, for which the solubility product turns out:
(C)
In such a way, as ammonium, magnesium and arsenate ions are in 1:1:1 molar ratio, they have the same concentrations, for which the solubility product turns out:
(D)
In such a way, as the involved ions are in 2:3 molar ratio, La ion is twice the molar solubility and MoOs ion is three times it, for which the solubility product turns out:
Best regards.
Answer:
Density, melting point. and magnetic properties
Explanation:
I can think of three ways.
1. Density
The density of Cu₂S is 5.6 g/cm³; that of CuS is 4.76 g/cm³.
It should be possible to distinguish these even with high school equipment.
2. Melting point
Cu₂S melts at 1130 °C (yellowish-red); CuS decomposes at 500 °C (faint red).
A Bunsen burner can easily reach these temperatures.
3. Magnetic properties
You can use a Gouy balance to measure the magnetic susceptibilities.
In Cu₂S the Cu⁺ ion has a d¹⁰ electron configuration, so all the electrons are paired and the solid is diamagnetic.
In CuS the Cu²⁺ ion has a d⁹ electron configuration, so all there is an unpaired electron and the solid is paramagnetic.
A sample of Cu₂S will be repelled by the magnetic field and show a decrease in weight.
A sample of CuS will be attracted by the magnetic field and show an increase in weight.
In the picture below, you can see the sample partially suspended between the poles of an electromagnet.