Answer:
0.0365
Explanation:
Three significant figures after the decimal include all numbers except the zeros before other numbers.
For example 0.000003431232 to three significant figures would be 0.00000343. However if the numbers are before the decimal, the zeros are included, for example 19828300 to three significant numbers would be 19800000.
Answer: D. A neutron has no charge
Explanation: Neutrons are subatomic particles found inside the nucleus of an atom. This particle is neutral and has no charge at all. That is the reason why the nucleus is positively charge since only the protons exhibits a charge and the neutrons carries no charge.
The answer is lead.
Every element in Group 14 (Group IVA) has four valence electrons, s^(2)p^(2)<span>.</span>
The percentage of Calcium carbonate in chalk = 100%
<h3>Further explanation</h3>
Given
1.51 g piece of chalk produces 0.665 g of carbon dioxide
Required
percentage of calcium carbonate
Solution
Reaction
CaCO3 (s) + 2 HCl (aq) → CaCl2 (aq) + H2O (l) + CO2 (g)
mol CO2 :
= 0.665 g : 44 g/mol
= 0.015
From the equation, mol CaCO3 = mol CO2 = 0.015
mass CaCO3 :
= mol x MW
= 0.015 x 100
= 1.5 g
