Answer:
An atom is the smallest particle of an element
Answer:
1x10^-8 M
Explanation:
Since the solution turns blue, it mean the solution is a base.
Now, to know which option is correct, we need to determine the pH of each solution. This is illustrated below:
1. Concentration of Hydrogen ion, [H+] = 1x10^-2 M
pH =..?
pH = - log [H+]
pH = - log 1x10^-2
pH = 2
2. Concentration of Hydrogen ion, [H+] = 5x10-2 M
pH =..?
pH = - log [H+]
pH = - log 5x10^-2
pH = 1.3
3. Concentration of Hydrogen ion, [H+] = 5x10 M
pH =..?
pH = - log [H+]
pH = - log 5x10
pH = - 1.7
4. Concentration of Hydrogen ion, [H+] = 1x10-8 M
pH =..?
pH = - log [H+]
pH = - log 1x10^-8
pH = 8
A pH reading shows if the solution is acidic or basic. A pH reading between 0 and 6 indicates an acidic solution, a pH reading of 7 indicates a neutral solution while a pH reading between 8 and 14 indicates a basic solution.
From the above calculations, the pH reading indicates a basic solution when the hydrogen ion concentration was 1x10^-8 M.
Answer:
ΔS = +541.3Jmol⁻¹K⁻¹
Explanation:
Given parameters:
Standard Entropy of Fe₂O₃ = 90Jmol⁻¹K⁻¹
Standard Entropy of C = 5.7Jmol⁻¹K⁻¹
Standard Entropy of Fe = 27.2Jmol⁻¹K⁻¹
Standard Entropy of CO = 198Jmol⁻¹K⁻¹
To find the entropy change of the reaction, we first write a balanced reaction equation:
Fe₂O₃ + 3C → 2Fe + 3CO
To calculate the entropy change of the reaction we simply use the equation below:
ΔS = ∑S
- ∑S
Therefore:
ΔS = [(2x27.2) + (3x198)] - [(90) + (3x5.7)] = 648.4 - 107.1
ΔS = +541.3Jmol⁻¹K⁻¹
Yes, you should memorize them. While it is easy to predict them by looking at a periodic table, you should still have a strong grasp of simpler chemistry such as this before more challenging topics are taught.
Answer:

Explanation:
To convert from moles to grams, the molar mass must be used.
1. Find Molar Mass
The compound is iron (III) chloride: FeCl₃
First, find the molar masses of the individual elements in the compound: iron (Fe) and chlorine (Cl).
There are 3 atoms of chlorine, denoted by the subscript after Cl. Multiply the molar mass of chlorine by 3 and add iron's molar mass.
- FeCl₃: 3(35.45 g/mol)+(55.84 g/mol)=162.19 g/mol
This number tells us the grams of FeCl₃ in 1 mole.
2. Calculate Moles
Use the number as a ratio.

Multiply by the given number of grams, 345.0.

Flip the fraction so the grams of FeCl₃ will cancel.



Divide.

3. Round
The original measurement of grams, 345.0, has 4 significant figures. We must round our answer to 4 sig figs.
For the answer we calculated, that is the thousandth place.
The 1 in the ten thousandth place tells us to leave the 7 in the thousandth place.

There are about <u>2.127 mole</u>s of iron (III) chloride in 345.0 grams.