Answer:
the answer is 1 sir BC i t is BC it is BC its 2
Using the periodic table to choose the element that matches each description include the following below:
<h3>What is a Periodic table?</h3>
This contains elements which are arranged according to the order of their atomic number in a tabular form. There are 18 groups which are the vertical columns present while there are 8 periods which are the horizontal rows present in the periodic table.
Example of an alkali metal is potassium while the non reactive ones include argon, neon etc. Examples of halogens include chlorine, iodine etc. are the ones which have seven electrons in their outer electron shells thereby just requiring one electron to achieve to obtain a stable octet configuration.
These are therefore the elements which match the descriptions provided in this case and is the most appropriate choice.
Read more about Periodic table here brainly.com/question/15987580
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Answer:
The law of conservation of mass states that matter can not be created or destroyed in a chemical reaction.
Explanation:
Answer:
0.74 grams of methane
Explanation:
The balanced equation of the combustion reaction of methane with oxygen is:
it is clear that 1 mol of CH₄ reacts with 2 mol of O₂.
firstly, we need to calculate the number of moles of both
for CH₄:
number of moles = mass / molar mass = (3.00 g) / (16.00 g/mol) = 0.1875 mol.
for O₂:
number of moles = mass / molar mass = (9.00 g) / (32.00 g/mol) = 0.2812 mol.
- it is clear that O₂ is the limiting reactant and methane will leftover.
using cross multiplication
1 mol of CH₄ needs → 2 mol of O₂
??? mol of CH₄ needs → 0.2812 mol of O₂
∴ the number of mol of CH₄ needed = (0.2812 * 1) / 2 = 0.1406 mol
so 0.14 mol will react and the remaining CH₄
mol of CH₄ left over = 0.1875 -0.1406 = 0.0469 mol
now we convert moles into grams
mass of CH₄ left over = no. of mol of CH₄ left over * molar mass
= 0.0469 mol * 16 g/mol = 0.7504 g
So, the right choice is 0.74 grams of methane
