C
The high conductivity of silver does not promote its use in jewelry.
Characteristics used to classify stars include color, temperature, size, composition, and brightness. Stars vary in their chemical composition. Astronomers use spectrographs to determine the elements found in stars.
pH of mixed solution = 4.3
<h3>Further explanation
</h3>
A buffer solution is a solution that can maintain a good pH value due to the addition of a little acid or a little base or dilution.
The buffer solution can be acidic or basic
Acid buffer solution consists of weak acids and their salts.
valence according to the amount of salt anion
mol CH₃COOH = 25 ml x 0.9 = 22.5 mlmol
mol NaOH = 25 ml x 0.45 = 11.25 mlmol
ICE method :
Reaction
NaOH + CH₃COOH ---> CH₃COONa + H₂O
11.25 22.5
11.25 11.25 11.25 11.25
11.25 11.25 11.25
mol acid = 11.25, mol salt = 11.25, Ka CH₃COOH = 5.10⁻⁵
Then [H⁺]=
Natural abundance of oxygen I think
The liters in 3.25 g of ammonia 4.28 L
<u><em>calculation</em></u>
Step 1: find moles of ammonia
moles = mass÷ molar mass
From periodic table the molar mass of ammonia (NH₃) = 14 +(1×3 ) = 17 g/mol
3.25 g÷ 17 g/mol = 0.191 moles
Step 2: find the number of liters of ammonia
that is at STP 1 moles = 22.4 L
0.191 moles = ? L
<em>by cross multiplication</em>
={( 0.191 moles ×22.4 L) / 1 mole} = 4.28 L