What do you need to know how to do
<span>Problem 1) From the given options the one that is proper of a chemist is the option B. testing a sample of water form a well. This activity belongs to the field called analytical chemistry which uses special techniques (instruments and processes) to study (separate, identify and quantify matter).
Problem 2) The only of the given procedures that involves a physical change in one substance is the option D. grinding chalk into a fine powder. In this process the molecules remain being the same (same atoms bonded in the number and way).</span>
Answer:
Explanation:
(a) Balanced equation
3NaOH + H₃PO₄ ⟶ Na₃PO₄ + 3H₂O
(b) Moles of NaOH
(c) Moles of H₃PO₄
The molar ratio is 1 mol H₃PO₄:3 mol NaOH.
(d) Molar concentration of H₃PO₄
Atoms of Mg = mol * L
mol of Mg =
=
= 2 mol
∴ atoms of Mg = 2 mol * ( 6.02 x 10²³)
= 1.204 x 10²⁴
elements have equal number of protons and neutrons
the condensed format is when the closest noble gas with the closest electron configuration is given, this closest noble gas atomic number should be lesser than the atoms atomic number
atomic number of Kr is 36
1 electron in 5s subshell and 7 electrons in 4d subshell.
there's a total of 36 + 1 + 7 = 44 electrons
atomic number of the atom is 44
element with atomic number 44 is Ruthenium - Ru
answer is Ru
