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.
Dissolver is the answer i think because that is what disovling means
Answer:
1+
Explanation:
the number of protons tells you which element it is in the periodic table, you can notice that there is 1 less electron that then there is protons which means that the element had to give 1 electron away. When you get rid of 1 e- you have 1 proton more that electrons so that's why it's 1+
also the element is Cr
Answer:
Correct option -D
Explanation:
Here, A kinetics experiment is set up is set up to collect the gas that is generated from the cacarbonate and methanoic acid.
Among the given conditions, decreasing the particle size of calcium carbonate only increases the production of gas.
Smaller particles of reactant increases the surface area then followed by rate of reaction will be increases it leads to increases the production of gas.
Therefore, the suitable experimental condition most likely to increase the gas production is-
Decreasing the particle size of the 
by grinding it into a fine powder.
Hence, correct option -D.
