<h3>
Answer:</h3>
0.699 mole CaCl₂
<h3>
Explanation:</h3>
To get the number of moles we use the Avogadro's number.
Avogadro's number is 6.022 x 10^23.
But, 1 mole of a compound contains 6.022 x 10^23 molecules
In this case;
we are given 4.21 × 10^23 molecules of CaCl₂
Therefore, to get the number of moles
Moles = Number of molecules ÷ Avogadro's constant
= 4.21 × 10^23 molecules ÷ 6.022 x 10^23 molecules/mole
= 0.699 mole CaCl₂
Hence, the number of moles is 0.699 mole of CaCl₂
Following reactions are involved in present reaction
1) A<span>g+(aq) + Li(s) → Ag(s) + Li+(aq) </span><span>− 384.4kJ
2) </span><span>2Fe(s) + 2Na+(aq) → Fe2+(aq) + 2Na(s) + 392.3kJ
</span>3) <span>2K(s) + 2H2O(l) → 2KOH(aq) +H2(g) −393.1kJ
In above reaction, reaction 1 and 3 has negative value of </span>δh∘f, while reaction 2 has posiyive value of <span>δh∘f. As per the sign convention positive sign indicates that heat is given out during the reaction, while negative sign indicates heat is to be supplied for reaction to occur. In alternative words, product formed in reaction 2 is stable as compared to reactant. Hence, it is thermodynamically favorable. </span>
The answer would be 0.25 g/mL.
I determined the density by dividing the mass by the volume which gives you the density. D = mass/volume.
<span>6 g / 24 mL = 0.25 g/mL
</span>
Answer:
The inner diameter of the tube is 0.4410 cm.
Explanation:
Height upto which mercury is filled = 12.7 cm
Mass of mercury = 105.5 g
Density of mercury = 13.6 g/mL =
Volume of mercury:

A mercury in cylindrical glass tube is at height of 12.7 cm.
The radius of the inner diameter of the glass tube = r
Volume of cylinder = 

r = 0.4410 cm.