Mass number = protons + neutrons
mass number = 5 + 7
mass number = 12
Answer:
m = 31.284 grams
Explanation:
Given that,
The dimension of a magnesium block is 2.00 cm x 3.00 cm x 3.00 cm.
The density of magnesium is, d = 1.738 g/cm³
We need to find the mass of the magnesium block. We know that the density of an object is given by its mass per unit its volume. So,
So, the mass of the block is 31.284 grams.
Empirical formula is the simplest ratio of components making up a compound.
The percentage composition of each element has been given
therefore the mass present of each element in 100 g of compound is
B N H
mass 40.28 g 52.20 g 7.53 g
number of moles
40.28 g / 11 g/mol 52.20 g / 14 g/mol 7.53 g / 1 g/mol
= 3.662 mol = 3.729 mol = 7.53 mol
divide the number of moles by the least number of moles, that is 3.662
3.662 / 3.662 3.729 / 3.662 7.53 / 3.662
= 1.000 = 1.018 = 2.056
the ratio of the elements after rounding off to the nearest whole number is
B : N : H = 1 : 1 : 2
therefore empirical formula for the compound is B₁N₁H₂
that can be written as BNH₂
INFORMATION:
We must find the number of valence electrons for magnesium
STEP BY STEP EXPLANATION:
In order to know the number of valence electrons for Mg, we need to locate the element in the periodic table
Since Mg is in the second group of the periodic table, it has two valence electrons.
ANSWER:
B) 2
Respuesta:
2400 mL
Explicación:
Paso 1: Información dada
- Volumen de solución: 3 L (3000 mL)
- Concentración de naranja: 20 % v/v
Paso 2: Calcular el volumen de naranja
La concentración de naranja es de 20 % v/v, es decir, cada 100 mL de solución hay 20 mL de naranja.
3000 mL Sol × 20 mL Naranja/100 mL Solución = 600 mL Naranja
Paso 3: Calcular el volumn de agua
El volumen de soluciónes igual a la suma de los volúmenes de naranja y agua.
VSolución = VNaranja + VAgua
VAgua = VSolución - VNaranja
VAgua = 3000 mL - 600 mL = 2400 mL
