The chemical reaction is written as:
2Zn + O2 = 2ZnO
We are given the amount of the product to be produced from the reaction. We use this value and the relation of the substances in the reaction to calculate what is asked. We do as follows:
2.10 g ZnO ( 1 mol / 81.408 g ) ( 1 mol O2 / 2 mol ZnO ) ( 32 g / 1 mol ) = 0.414 g O2 is needed
This problem is asking for the percent by mass of hydrogen in hydrofluoric acid. At the end, the answer turns out to be D. 5% as shown below:
<h3>Percent compositions:</h3>
In chemistry, percent compositions are used for us to know the relative amount of a specific element in a compound. In order to do so for hydrogen, we use the following formula, which can also be applied to any other element in a given compound:
Where stands for the atomic mass of hydrogen and for the molar mass of hydrofluoric acid. In such a way, we plug in the atomic masses of hydrogen (1.01 g/mol) and fluorine (19.0 g/mol) to obtain:
Learn more about percent compositions: brainly.com/question/12247957
Conductivity is the ability of a substance to allow charge or electricity to pass through it. Metals have a lot of free electrons and are considered as good conductors while non-metals do not conduct electricity
1) In the given examples:
Al is a metal, Na is an alkali metal while P is a non-metal
The decreasing order of conductivity would be:
Al > Na > P
2)
Both Al and Ga are metals while B is metalloid.
Among Al and Ga, Al is a solid at room temperature and a better conductor of electricity. hence the decreasing order would be:
Al > Ga > B