Atomic radii increase when going down a group and decreases when going towards the anion periods. So A and D.
4. A
because PbCl2 is an ionic compound and it's solid, so it's a substance.
It cannot be mixture, because it's a pure molecule.
5. D
despite that both substances are gases, colorless they are different molecules, so they should have different either chemical and physical properties
6. C
this substance made from W atoms and others are made from molecules
Exothermic reaction is where there is release of energy during a reaction
The enthalpy of exothermic reaction is negative
The relation between energy of products, reactants and enthalpy of reaction is
Enthalpy of reaction = sum of enthalpy of formation of products - sum of enthalpy of formation of reactants
.
As enthalpy of reaction is negative, it means the enthalpy of products is less than the enthalpy of reactants so answer is
:
In an exothermic reaction the energy of the product is less than the energy of the reactants.
Answer:
- <em>The net charge of the ionic compound calcium fluoride is </em><u><em>zero (0).</em></u>
<em>Explanation:</em>
<em>Ionic compounds,</em> such as covalent ones, have zero net charge; this is, they are neutral.
Substances with net positive charge are cations and substances with net negative charge are anions.
The charges in the <em>ionic compound calcium flouride</em> are distributed in this way:
- Calcium charge: Ca²⁺: this is, each calcium ion has a 2 positive charge
- Fluoride charge: F⁻: each fluoride ion has a 1 negative charge.
- Then, the <em>net charge</em> is: 1 × (2+) + 2 × (1-) = +2 - 2 = 0.
So, a two positve charge, from one calcium ion, is equal to two negative charges, from two fluoride tions, yielding a <u>zero net charge</u>.
Answer:
Cloruro de sodio y fluoruro de sodio.
Dióxido de carbono y monóxido de hidrógeno.
Explicación:
El cloruro de sodio y el fluoruro de sodio son los compuestos que tienen enlaces iónicos. Estos compuestos iónicos se utilizan para diferentes actividades de nuestra vida diaria. El cloruro de sodio se usa para cocinar y el fluoruro de sodio se usa en la pasta de dientes para limpiar nuestros dientes. El dióxido de carbono y el monóxido de hidrógeno son compuestos que tienen enlaces covalentes. El dióxido de carbono se usa en refrescos / refrescos y algunos otros líquidos que se pueden usar en la vida diaria. El monóxido de hidrógeno es el agua pura que bebemos todos los días en nuestra vida diaria y es muy importante para nuestra supervivencia.
