Answer:
The answer to your question is the letter C. 2.906 x 10²³ atoms
Explanation:
Data
mass of Lead = 100 g
The Number of atoms = ?
Process
1.- Look for the atomic number of Lead in the periodic table
Atomic number = 207.2 g
2.- Use proportions and the Avogadro's number to calculate the number of atoms.
207.2 g ------------------ 6.023 x 10²³ atoms
100 g ----------------- x
x = (100 x 6.023 x 10²³) / 207.2
x = 6.025 x 10²⁵ / 207.2
x = 2.906 x 10²³ atoms
Answer:
The answer to this question is given below in the explanation section.
Explanation:
The Bohr model depicts an atom as a small, positively charged nucleus surrounded by electrons.These electrons travel in circular orbit around the nucleus similar in structure to the solar system,except electrostatic forces rather than gravity provide attraction.Electron orbit around the nucleus resembles that of planets around the sun in the solar system.
The Bohr model was an improvement on the earlier cubic model(1902),the plum pudding model(1904) the saturnine model (1904) the rutherford model (1911) since the Bohr model is a quantum physics based modification of the Rutherford may source combine the two:the Rutherford-Bohr model
Although revolutionary at the time,the Bohr model is a relatively primitive model of the hydrogen atom compared to the valence shell atom.As an initial hypothesis it was derived as a first order approximation to describe the hydrogen atom.Due to its simplicity and correct results for selected systems.
In 913 Bohr suggested that electrons could only have certain classical motions:
- Electrons in atoms orbit the nucleus.
- The electrons can only orbit stably,without radiating in certain orbits at a certain discrete set of distances from the nucleus.These orbit are associated with definite energies and are also called energy shells or energy levels.
- Electrons can only gives or lose energy by jumping from one allowed orbit to another,absorbing or emitting electromagnetic radiation with a frequency (v) determined by the energy difference of the levels according to the plank relation.
Answer:
2HNO3+Ca(OH)2 = Ca(NO3)2+2H2O
Explanation:
The reaction between Nitric acid(HNO3)and Calcium hydroxide(Ca(OH)2) gives Calcium Nitrate( Ca(NO3)2 and Water( H2O)
KOH is a strong base and HBr is a strong acid and completely dissociates.
The balanced equation for the reaction is;
KOH + HBr ---> KBr + H₂O
Stoichiometry of acid to base is 1:1
The number of KOH moles reacted - 0.50 M / 1000 mL/L x 48.0 mL = 0.024 mol
number of HBr moles reacted - 0.25 M/ 1000 mL/L x 96.0 mL = 0.024 mol
the number of H⁺ ions are equal to number of OH⁻ ions.
Then the solution is neutral.
pH of neutral solutions at 25 °C is 7.
Therefore pH is 7
Answer:
Explanation:
In a chemical change through chemical reactions, a new kind of matter forms. When a paint is mixed together, a physical change has occurred and not a chemical change. The different color one perceives is just a mere overlap between the reflected white and red color which produces another hue.
Not all color changes infers a chemical reaction. A paint is a complex mixture on its own.
