The model after John Dalton's was J.J Thompson's plum podding model in 1897, which described electrons as dots or raisins(if you will) in a circle shaped pudding that was entirely positive using a Cathode Ray Tube(shot cathode rays between magnets). The model after that is the Niels Bohr model in 1913, which depicts atoms like positively charged center called the nucleus with negatively charged particles called electrons in a shell or cloud.
Answer: -
37.5 g of NaCl are in 250 g of a 15.0% (by weight) solution.
Explanation: -
Total mass = 250 g
Percentage of NaCl = 15.0 %
= 
Thus 
= 
Number of grams of NaCl present = 
= 37.5 g
The statement that identifies an oxidation-reduction reaction is a reaction in which oxidation numbers change (option C).
<h3>What is a redox reaction?</h3>
A redox or oxidation-reduction reaction is a chemical reaction in which some of the atoms have their oxidation number changed.
In a chemical reaction that involves oxidation and reduction, the oxidation number of the involved ions either decreases or increases.
Therefore, the statement that identifies an oxidation-reduction reaction is a reaction in which oxidation numbers change.
Learn more about redox reaction at: brainly.com/question/13293425
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Answer:
The number of moles of benzaldehyde = 0.0253 moles
Explanation:
The molecular formula of benzaldehyde is C₇H₆O
Its molecular mass is calculated from the atomic masses of the constituent atoms.
C = 12.0 g: H = 1.0 g; O = 16.0 g
Molecular mass = ( 12 * 7) + (1 * 6) + (16 * 1) = 106.0 g/mol
Number of moles of substance = mass of substance/ molar mass of the substance
mass of benzaldehyde = 2.68; molar mass = 106.0 g/mol
Number of moles of benzaldehyde = 2.68 g/ 106 g/mol = 0.0253 moles
Therefore, the number of moles of benzaldehyde = 0.0253 moles
