A. All atoms of all elements are the same size. B. Atoms of different<span> elements always combine in one-one ratios. C. Atoms of the same element are always</span>identical<span>. Which of the following was originally a part of Dalton's atomic theory, but had to be revised about a century ago?</span>
Organelles are able to use photosynthesis because they have chlorophyll produced by the chloroplasts
<u>Answer:</u>
<u>For a:</u> The increasing of atomic radius is:
Al < Mg < Na
<u>For b:</u> The pH of the solution of sodium oxide is greater than 7.
<u>Explanation:</u>
Atomic radius is defined as the distance of the nucleus to the outermost shell containing electrons.
It decreases as we move from left to right in a period because electrons get added up in the same shell and effective nuclear charge increased which results in the shrinkage of the atom.
Sodium lies in Period 3, group 1. Its atomic radius is 1.90
Magnesium lies in Period 3, group 2. Its atomic radius is 1.60
Aluminium lies in Period 3, group 3. Its atomic radius is 1.32
The increasing of atomic radius will be:
Al < Mg < Na
The mathematical values proves the result.
There are 3 types of solution based on pH:
- If pH > 7, the solution is basic in nature.
- If pH < 7, the solution is acidic in nature.
- If pH = 7, the solution is neutral in nature.
When a metal reacts with oxygen present in air, it forms basic oxide which simply means when they react with water, they form basic solution.
The chemical equation for the reaction of sodium (metal) with oxygen present in air and reaction with water of the product so formed are as follows:
Sodium forms a basic solution when its oxide reacts with water, therefore the pH of the solution will be greater than 7.
The Brønsted-Lowry base in the given reaction is NH₂⁻. The correct option is the fourth option NH2−
To determine which is the Brønsted-Lowry base in the given reaction:
NH2−+CH3OH→NH3+CH3O−
First, we will write the equation for the reaction properly
The equation is:
NH₂⁻ + CH₃OH → NH₃ + CH₃O⁻
Now, to determine which among the species in the above reaction is the Brønsted-Lowry base, we will start by defining what a <em>Brønsted-Lowry base</em><em> </em>is.
A Brønsted-Lowry base is any species that is capable of accepting a proton, which requires a lone pair of electrons to bond to the H⁺.
In simple terms, a Brønsted-Lowry base is a proton acceptor.
In the above reaction, NH₂⁻ is the species that is capable of accepting a proton and it has a lone pair of electrons to bond to the H⁺.
∴ NH₂⁻ is the Brønsted-Lowry base in the reaction
Hence, the Brønsted-Lowry base in the given reaction is NH₂⁻. The correct option is the fourth option NH2−
Learn more here: brainly.com/question/13017688
Answer:
The change in entropy in the system is -231.5 J/K
Explanation:
Step 1: Data given
The normal boiling point of ethanol (C2H5OH) is 78.3 °C = 351.45 K
The molar enthalpy of vaporization of ethanol is 38.56 kJ/mol = 38560 J/mol
Mass of ethanol = 97.2 grams
Pressure = 1 atm
Step 2: Calculate the entropy change of vaporization
The entropy change of vaporization = molar enthalpy of vaporization of ethanol / temperature
The entropy change of vaporization = 38560 J/mol / 351.45 K
The entropy change of vaporization = -109.72 J/k*mol
Step 3: Calculate moles of ethanol
Moles ethanol = mass / molar mass ethanol
Moles ethanol = 97.2 grams / 46.07 g/mol
Moles ethanol = 2.11 moles
Step 4: Calculate change in entropy
For 1 mol = -109.72 J/K*mol
For 2.11 moles = -231.5 J/K
The change in entropy in the system is -231.5 J/K