2 C2H6 + 7 026 H2O + 4 CO2 If 5.25 moles of ethane (C2H6) and 15.0 moles of oxygen are reacted,
which is the limiting reactant?

Oxygen is limiting reactant

Explanation:

Based on the chemical reaction:

2C2H6 + 7O2 → 6H2O + 4CO2

2 mole of ethane reacts with 7 moles of oxygen

For a complete reaction of 5.25 moles of ethane are required:

5.25 moles Ethane * (7mol Oxygen / 2mol Ethane) = 18.38 moles of oxygen

As there are just 15.0 moles of oxygen

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.