Answer ;
-An element is a substance containing only one type of atom, for example; H2 or 02 (consisting of atoms that all have the same number of protons).
-Microscopic, single atom of that element
-Macroscopic, sample of that element large enough to weigh on a balance
- A substance that cannot be broken down chemically; e.g; sodium metal,
Explanation;
-An element is a substance whose atoms all have the same number of protons: another way of saying this is that all of a particular element's atoms have the same atomic number. Elements are chemically the simplest substances and hence cannot be broken down using chemical reactions.
-An element is uniquely determined by the number of protons in the nuclei of its atoms.
Answer:
C
Explanation:
Under ordinary conditions, a substance will sublime rather than melt if its critical point occurs at a pressure above atmospheric pressure.
At conditions below the triple point that is under ordinary conditions , it is a solid to gas transition, vaporization only occurs above the triple point.
Hence the most correct answer is Option C.
Answer:
67.88% is the percent yield.
Explanation:
Moles of methane = 
According to reaction,1 mole of methane gives 1 mole of carbon dioxide gas, then 3.75 moles of methane will give :
of carbon dioxide gas
Mass of 3.75 moles of carbon dioxide gas:
3.75 mol × 44 g/mol = 165 g
Theoretical yield of the carbon dioxide gas = 165 g
Experimental yield of the carbon dioxide gas = 112 g
The percentage yield of the reaction :
67.88% is the percent yield.
A strong base turns phenolphthalein pink, so the answer is (3) NaOH
Combustion equation of Methane:
CH₄ + 2 O₂ → CO₂ + 2 H₂O
So from the equation we can see that methane gas (CH₄) burned in air to give carbon dioxide and water
The provided choices are 1. CO₂ 2. H₂ 3. H₂O
So from the choices the correct answer will be 1 and 3 only
