Answer:
Substances 1 and 2
Explanation:
an element only has 1 kind of atoms :3
Answer:
C
Explanation:
CH₄ is the formula for methane
Answer:
Neutron, neutral subatomic particle that is a constituent of every atomic nucleus except ordinary hydrogen. It has no electric charge and a rest mass equal to 1.67493 × 10−27 kg—marginally greater than that of the proton but nearly 1,839 times greater than that of the electron.
First, we need to get moles of HA =molarity * volume
= 0.1 m * 0.075 L = 0.0075 moles
moles of NaOH = molarity * volume
= 0.1 * 0.03 L = 0.003 moles
from the reaction equation:
HA(aq) + NaOH(aq) → NaA(aq) + H2O(l)
that means the final moles' HA = 0.0075 - 0.003 =0.0045 moles
when the total volume is = 0.075 + 0.03 L = 0.105 L
∴ [HA] = moles / volume
= 0.0045 / 0.105 L = 0.043 m
[A^-] = 0.003 / 0.105 L = 0.029 m
then by using H-H equation:
PH = Pka + ㏒[A^-] / [HA]
by substitution, we can get Pka:
5.5 = Pka+ ㏒ (0.029 /0.043)
∴ Pka = 5.67
when Pka = - ㏒Ka
5.67 = -㏒ Ka
∴Ka = 2 x 10^-6