Answer:
Option A (0.043 g) is the correct answer.
Explanation:
Given:
= 43 mg
As we know,
then,
⇒ 
Thus, the above is the correct alternative.
Answer:
20.27 mol
Explanation:
454 L x (1 mol/22.4 L) = 20.27 mol
Chemical changes only happen when the object changes form. Color is a physical property because you're not changing the object that you have, compressibility is also a physical property because you still have the same substance before and sfter, malleability again is another physical. Heat of combustion is physical, when you burn things it changes the substance. :)
Answer:
1. Mass of potassium (K) = 203.32 g
2. Number of mole of As = 7.53 moles
Explanation:
1. Determination of the mass of potassium (K)
Molar mass of K = 39.1 g/mol
Number of mole of K = 5.2 moles
Mass of K =.?
Mole = mass / Molar mass
5.2 = mass of K / 39.1
Cross multiply
Mass of K = 5.2 × 39.1
Mass of potassium (K) = 203.32 g
2. Determination of the number of mole of Arsenic (As)
Molar mass of As = 74.92 g/mol
Mass of As = 563.9 g
Number of mole of As =.?
Mole = mass /Molar mass
Number of mole of As = 563.9 / 74.92
Number of mole of As = 7.53 moles
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.
.
