To make sure no cracks are in the crucible and also to remove any moisture present in the crucible by the process of heating.
Answer:
Carbon - 14
Oxygen - 16
Nitrogen - 15
Sulphur - 16
Explanation:
The question above is related to the "Periodic Table of Elements" which shows the proper arrangement of elements in a table. Every element falls on a<em> group/family</em> within the table. Each group has its own number, and the table has a total of<u> 18 groups</u><em> (from left to right). </em>They are classified according to <em>similarities in their characteristics</em>. For example, group 1 is composed of <em>alkali metals</em> while group 2 is composed of<em> alkali earth metals</em>.
When solutions of sodium sulfide and copper(ii) sulfate are mixed, a precipitate of copper(ii) sulfide is formed. The net ionic equation for this reaction is Cu⁺² (aq) + S⁻² (aq) → CuS (s).
<h3>What is Balanced Chemical Equation ?</h3>
The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.
Now first write the balanced chemical equation
CuSO₄ (aq) + Na₂S (aq) → CuS(s) + Na₂SO₄ (aq)
Now write the net ionic equation
Cu⁺² (aq) + SO₄⁻² (aq) + 2Na⁺ (aq) + S⁻² (aq) → CuS (s) + 2Na⁺ + SO₄⁻² (aq)
So the net ionic equation is
Cu⁺² (aq) + S⁻² (aq) → CuS (s)
Thus from the above conclusion we can say that When solutions of sodium sulfide and copper(ii) sulfate are mixed, a precipitate of copper(ii) sulfide is formed. The net ionic equation for this reaction is Cu⁺² (aq) + S⁻² (aq) → CuS (s).
Learn more about the Balanced Chemical Equation here: brainly.com/question/26694427
#SPJ4
Answer:
1.51 x 10²⁴atoms
Explanation:
Given parameters:
Number of moles of Cr = 2.50mol
Solution;
what is a mole;
a mole of any substance is the amount of substance that contains the avogadro's number of particles which is 6.02 x 10²³ particles
The particles here can be atoms, protons, neutrons, electrons e.t.c
1 mole contains 6.02 x 10²³ atoms
2.5 moles will contain 2.5 x 6.02 x 10²³ = 1.51 x 10²⁴atoms
