Explanation:
We have to find the number of molecules that are present in 0.54 g of Ca(NO₃)₂.
First we have to convert the mass of our sample into moles of Ca(NO₃)₂. We will use the molar mass of Ca(NO₃)₂ to do that.
molar mass of Ca = 40.08 g/mol
molar mass of N = 14.01 g/mol
molar mass of O = 16.00 g/mol
molar mass of Ca(NO₃)₂ = 1 * 40.08 g/mol + 2 * 14.01 g/mol + 6 * 16.00 g/mol
molar mass of Ca(NO₃)₂ = 164.10 g/mol
mass of Ca(NO₃)₂ = 0.54 g
moles of Ca(NO₃)₂ = 0.54 g * 1 mol/(164.10 g)
moles of Ca(NO₃)₂ = 0.00329 moles
According to Avogadro's number there are 6.022 *10^23 molecules in 1 mol of molecules. We can use that relationship to find the number of molecules that are present in our sample.
6.022 *10^23 molecules = 1 mol
molecules of Ca(NO₃)₂ = 0.00329 moles * 6.022 *10^23 molecules/(1 mol)
molecules of Ca(NO₃)₂ = 2.0 * 10^21 molecules
Answer: there are 2.0 * 10^21 molecules of Ca(NO₃)₂ in 0.54 g of it.
Answer:
A physical change is a change from one state of matter to another; a chemical change results in a new substance formed.
<u><em>Physical properties:</em></u>
Physical properties are those which have same composition. In other words, composition does not change, only state may be change like solid to liquid, liquid to gas, solid to liquid etc.
<u><em>Example. </em></u>
Water when freezes into ice, it is physical change, just state is change.
<em><u>Chemical properties:</u></em>
The chemical properties depend upon composition.
<u>Example:</u>
Formation of precipitates is an example of chemical change.
Answer:
As per the given chemical equation, 1 mole of Cl₂ is formed when 87.9 kJ of heat is absorbed. 201.64 g of Cl₂ will be produced along with 250.0 kJ of heat in the given reaction.
Explanation:
Answer:
Atomic emission spectra are produced when excited electrons return to the ground state.
Explanation:
Answer: -
Molality of NaCl = 2.807 ×10⁻² m
Explanation: -
Molarity given = 2.800×10⁻² M
This means there are 2.800×10⁻² moles of NaCl per 1000 mL of solution.
Volume of water = 999.2 ml
Density of water = 0.9982 g/ml
Mass of water = Density of water x Volume of water
= 0.9982 g/ml x 999.2 ml
= 997.4 g
Thus 997.4 g of water has 2.800×10⁻² moles of NaCl.
1000 g of water has
x 2.800×10⁻² moles of NaCl.
= 2.807 ×10⁻² moles of NaCl.
Molality of NaCl = 2.807 ×10⁻² m