Answer:
Explanation:
D. 2 Fe's, 3 O's
An atom is the smallest indivisible particle of a substance. Most notations of elements in actual sense depicts the combining atoms.
In Fe₂O₃, the subscript gives the idea of the number of combining atoms and their combining ratios. Here, weh have 2 atoms of Fe and 3 atoms of Oxygen.
Activated carbon filters use chemical means to seperate impurities from air:
Chemical reactions occurs when compounds are formed. Activated carbon filters are made up of activated carbons in which impurities have been removed and the pores of the carbon structure have become widened. This leaves the carbon with much surface area for chemical reaction to occur between impurities and the carbon in form of chemical adsorption. One important thing to note is that, in chemical change, it is difficult to resolve the reactants after the product is formed. In physical change, simple seperation techniques are used to seperate the reactants out.
Answer:
6. d, 7. a
Explanation:
6. Molarity is a number of moles solute in 1 L solution.
7. 1 L solution - 2.5 mol K2CO3
20 L - x mol K2CO3
x =20*2.5/1 = 50 mol K2CO3
Molar mass(KCO3) = M(K) + M(C) + 3M(O)= 39 +12 +3*16= 99 g/mol
99 g/mol *50 mol = 4950 g KCO3 Closest answer is A.
Actually KCO3 does not exist, in reality it should be K2CO3.
The only liquid elements at standard temperature and pressure are bromine (Br) and mercury (Hg). Although, elements caesium (Cs), rubidium (Rb), Francium (Fr) and Gallium (Ga) become liquid at or just above room temperature.
Answer is: d) NaHCO₃ - sodium hydrogen carbonate or s<span>odium bicarbonate.
It is because other salt are made in reaction between strong base and strong acid and </span>sodium hydrogen carbonate is made from strong base (sodium hydroxide) and weak acid (carbonic acid).
Sodium bicarbonate<span> is an aqueous solution is used for cases of </span><span>acidosis.</span>
