Answer:
This question is incomplete but the correct option is B
Explanation:
This question is incomplete because of the absence of the "Reference Table S", however the question can still be answered in the absence of the table. The energy described in the question is the ionization energy (energy required to remove the most loosely bound electron in an atom). This question seeks to know the atom (from the options provided) with the least ionization energy.
Ionization energy increases from left to right across the period because it's easier to remove a single electron (valence electron) from the outermost shell than to remove two electrons from the same shell; thus the more the valence electrons (in a shell), the higher the ionization energy. Thus, bromine (Br) and tin (Sn) have high ionization energies because they have more number of electrons in there outermost shell.
<u>Berylium (Be) and strontium (Sr) are both in the group 2 of the periodic table because they both have 2 electrons in there outermost shell. Ionization energy decreases down a group. This is because the farther an electron is from the nucleus, the weaker the force of attraction between the nucleus and the electron. Thus, strontium (Sr) would have a lesser ionization energy between the two and would indeed have the least ionization among the options provided</u>. Hence, the correct option is B
Answer:
2%
Explanation:
.98 is 98% of one and therefore they are missing 2%
Answer:
.
Explanation:
Consider the oxidation state on each of the element:
Left-hand side:
- O: -2 (as in most compounds);
- Cr:
; - Fe: +2 (from the charge of the ion);
Right-hand side:
Change in oxidation state:
- Each Cr atom: decreases by 3 (reduction).
- Each Fe atom: increases by 1 (oxidation).
Changes in oxidation states shall balance each other in redox reactions. Thus, for each Cr atom on the left-hand side, there need to be three Fe atoms.
Assume that the coefficient of the most complex species 
is 1. There will be two Cr atoms and hence six Fe atoms on the left-hand side. Additionally, there are going to be seven O atoms.
Atoms are conserved in chemical reactions. As a result, the right-hand side of this equation will contain
- two Cr atoms,
- six Fe atoms, and
- seven O atoms.
O atoms seldom appear among the products in acidic environments; they rapidly combine with 
ions to produce water 
. Seven O atoms will make seven water molecules. That's fourteen H atoms and hence fourteen ions on the product side of this equation. Hence the balanced equation. Double check to ensure that the charges on the ions also balance.
.
Salt allows the ice cream to get colder because
Answer:
b) 18.5 g
Explanation:
The first step is the <u>calculation of number of moles</u> of 
with the molarity equation, so:
With the <u>volume in "L" units</u> (342.6 mL= 0.342 L ) we can <u>find the moles</u>, so:
Now, we have to calculate the <u>molar mass</u> to convert the moles to grams. For this we have to know the <u>atomic mass</u> of each atom:
Li ( 6.94 g/mol)
N (14 g/mol
O (16 g/mol)
With these values and the number of atoms in the molecule we can do the math:
(6.94 x 1) + ( 14 x 1) + (16 x 3 ) = 68.94 g/mol
The final step is the <u>calculation of the grams</u>, so:
<u>We will need 18.5 g of LiNO3 to do a 0.783 M solution with a volume 342.6 mL.</u>
