<span>Scientific notation is used to express large numbers in a way that is to use, readable, comparable to other numbers and convenient. It is especially useful for things that are very large and very small because it is very tedious to work with many zero's when completing complex math problems.</span>
The correct answer is A. It shows how electrons are distributed in the shells of an iron atom.
Explanation:
In the model described, the circles represent the orbitals or shells of the atom, while the dots represent the distribution of electrons (negatively charged sub-particles). Additionally, the description shows the general electronic configuration of this atom is 2, 8, 14, 2, which means in the first orbital there are two electrons, in the second there are eight electrons, in the third, there are fourteenth electrons and in the fifth orbital there are two electrons. This electronic configuration occurs in the atoms of iron. Also, this differs from Cobalt because in cobalt the third orbital has 15 electrons. Thus, the model "shows how electrons are distributed in the shells of an iron atom".
One of the clues are that there will be a change in temperature. Usually when a reaction takes place heat will be absorbed or released resulting in a change of temperature. Hope this helped!
Answer:
See explanation, some might be graded as wrong if it's an automatic grading system but most
Explanation:
1. lose
2. valence
3. noble (Atoms don't actually always do this, but since the word gas is after the blank, it is the only option)
4. 4
5. have
6. 10
5 and 6 are a little ambiguous and could have many answers
The molar mass of NO₂ is 46.0 g/mol
The molar mass of Pb (NO₃)₂ is 331.2 g/mol
First there is a need to find the number of moles of NO₂ via the stoichiometry of reaction:
2Pb(NO₃)₂ → 2PbO (s) + 4NO₂ (g) + 02 (g)
2 × 331.2 g = 4 × 46.0 g
16.87 g = x (mass of NO₂)
mass of NO₂ = 16.87 × 4 × 46 / 2 × 331.2
mass of NO₂ = 3104.08 / 662.4
mass of NO₂ = 4.686 g of NO₂
Now the number of moles are:
1 mole NO₂ = 46.0 g
x moles of NO₂ = 4.686 g
4.686 × 1 / 46.0 = 0.101 moles of NO₂
1 mole = 22.4 L (at STP)
0.101 moles of NO₂ = 0.101 × 22.4 / 1
= 2.26 L