Answer:
The oxidation state of N in the KNO3 is +5
Explanation:
Oxidation rules:
1. Oxygen is -2, unless in peroxides.
2. Group 1 metals = +1
3. Group 2 metals = +2
4. If the molecule is neutral, all of the oxidation numbers have to add up to zero.
5. If the molecule is charged, all of the oxidation numbers have to add up to the charge of the molecule.
So, the given formula represents the salt compound formula unit of potassium nitrate: KNO3
The formula unit is uncharged.
From our rules, we know that,
O = -2
And we can find K on the periodic table, in the first group, thus giving it a +1 charge. Now let's put it all together.
K = +1
N = x
O = -2
Let's take into account the number of atoms of each element we have and make an equation since we know everything has to add up to zero since the molecules are neutral.
+1 +x+3 (-2) = 0 (notice we multiplied 3 by -2 because in the formula we have 3 atoms of oxygen with -2 charge each)
x - 5 = 0
x = 5
Therefore, the oxidation number of N in KNO3 is +5.
Answer: B) The trees where peppered moths rest become lighter in color.
Answer: Mass number
If you look at the periodic table, you can simply find the mass number either on the top or bottom of the element.
Answer: Malleability
Explanation: cuz ... its right ... lol
Answer:
a) 
b) 
c) 
Explanation:
Hola.
Para resolver los numerales a), b) y c), debemos seguir los siguientes procedimientos:
a) En este caso, primeo calculamos la masa que 45.9 cm³ ocupan con una densidad 0.924 g/cm³ como se muestra a continuación:
Seguidamente, sabiendo que estos gramos ocupan 0.275 moles, podemos facilmente calcular la masa molar como la relación entre ellas:
b) En este caso, como se tienen 120 cm³ calculamos la nueva masa:
Luego, con la masa molar, las moles:
Finalmente, con el número de Avogadro, las moléculas presentes:
c) Aquí, consideramos que hay una molécula de la sustancia, por lo que usando el número de Avogadro, podemos calcular las moles que una molécula tiene:
Luego, usando la masa molar, calculamos la masa de una molécula:
¡Saludos!
