Answer:
Number of protons = 82
Explanation:
Given data:
Atomic number of Pb = 82
Mass number of Pb-207 = 207
Number of protons = ?
Solution:
An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.
Atomic number of Pb = number of protons or electrons
82 = number of protons or electrons
Mass number = Number of protons + number of neutron
207 = 82 + number of neutron
Number of neutrons = 207 - 82
Number of neutrons = 125
Answer:
the volume will expand
Explanation:
gas under pressure contracts, and expands with a lesser pressure
The molarity of H2SO4 is the number of moles in 1 L of solution.
The molarity is 2.0 mol/L
This means that there should be 2 moles in a 1 L solution to make up this molarity.
In this case we need to make up a 5 L solutions with that molarity. Then the amount of moles required are - 2 mol/L x 5 L = 10 mol
Respuesta:
16,7 mL
Explicación:
Paso 1: Información provista
- Concentración inicial (C₁): 6%
- Concentración final (C₂): 0,5%
- Volumen final (V₂): 200 mL
Paso 2: Calcular el volumen de la solución concentrada
Queremos preparar una solución diluida de hipoclorito de sodio a partir de una concentrada. Podemos calcular el volumen inicial que debemos tomar usando la regla de dilución.
C₁ × V₁ = C₂ × V₂
V₁ = C₂ × V₂ / C₁
V₁ = 0,5% × 200 mL / 6% = 16,7 mL
