Answer:
The modern understanding of an atom was developed by the quantum theory
Answer:
sulfur
Explanation:
sulfur has 4p electrons.
phosphorus has 3p electrons.
The question is asking which one has 4
<span>PV=nRT= a universal constant
For any condition
P1V1/n1T1=R
and
P2V2/n2T2=R
i.e
P1V1/n1T1=P2V2/n2T2
Becomes
V1/n1=V2/n2
rearranging and solving
V2=V1X(n2/n1)= 750 mLx((0.65+0.35)/(0.65))=1200ml=1.2L...2 sig figs</span>
An oxidation-reduction (redox<span>) </span>reaction<span> is a type of chemical </span>reaction<span> that involves a transfer of electrons between two species. An </span>oxidation<span>-reduction </span>reaction<span> is any chemical </span>reaction<span> in which the </span>oxidation<span> number of a molecule, atom, or ion changes by gaining or losing an electron</span>
To get the empirical formula, we need to know the ratio of the moles of both lead and sulfur.
First, lets get the mass of each:
mass of lead = mass of evaporating dish and lead - mass of empty dish
= <span>26.927 - 25.000 = 1.927 gm of lead (Pb)
mass of sulfur = mass of dish and lead sulfide - mass of dish and lead
= </span><span>27.485 - 26.927 = 0.558 gm of sulfur (S)
The next step is to get the number of moles in 1.927 gm of Pb and in 0.558 gm of S:
From the periodic table:
molar mass of lead = </span>207.2 gm<span>
molar mass of sulfur = 32 gm
number of moles = mass / molar mass
number of moles of Pb = 1.927 / 207.2 = </span>0.0093 moles<span>
number of moles of S = 0.558 / 32 = </span><span>0.0174 moles
The third step is to get the ratio between the moles by dividing the number of moles of each by the smaller of the two:
1 mole of Pb (</span>0.0093 / 0.0093) reacts with 0.0174 / 0.0093 = 1.99 (approximately 2 moles) of sulfur.
Final step is to write the empirical formula based on the ratio:
Lead sulfide compound is written as : PbS2