Answer:
a) pH = 4.213
b) % dis = 2 %
Explanation:
Ch3COONa → CH3COO- + Na+
CH3COOH ↔ CH3COO- + H3O+
∴ Ka = 1.8 E-5 = ([ CH3COO- ] * [ H3O+ ]) / [ CH3COOH ]
mass balance:
⇒ <em>C</em> CH3COOH + <em>C</em> CH3COONa = [ CH3COOH ] + [ CH3COO- ]
<em>∴ C </em>CH3COOH = 3.40 mM = 3.4 mmol/mL * ( mol/1000mmol)*(1000mL/L)
∴ <em>C</em> CH3COONa = 1.00 M = 1.00 mol/L = 1.00 mmol/mL
⇒ [ CH3COOH ] = 4.4 - [ CH3COO- ]
charge balance:
⇒ [ H3O+ ] + [ Na+ ] = [ CH3COO- ] + [ OH- ]....is negligible [ OH-], comes from water
⇒ [ CH3COO- ] = [ H3O+ ] + 1.00
⇒ Ka = (( [ H3O+ ] + 1 )* [ H3O+ ]) / ( 3.4 - [ H3O+])) = 1.8 E-5
⇒ [ H3O+ ]² + [ H3O+ ] = 6.12 E-5 - 1.8 E-5 [ H3O+ ]
⇒ [ H3O+ ]² + [ H3O+ ] - 6.12 E-5 = 0
⇒ [ H3O+ ] = 6.12 E-5 M
⇒ pH = - Log [ H3O+ ] = 4.213
b) (% dis)* mol acid = <em>C</em> CH3COOH = 3.4
∴ mol CH3COOH = 500*3.4 = 1700 mmol = 1.7 mol
⇒ % dis = 3.4 / 1.7 = 2 %
Answer: Alpha radiation
Explanation: Alpha decay : When a larger radioactive nuclei decays into smaller nuclei by releasing alpha radiation, the mass number and atomic number is reduced by 4 and 2 units respectively.
Beta decay : When a larger radioactive nuclei decays into smaller nuclei by releasing beta radiation, the atomic number is increased by 1 unit.
Gamma decay : When a larger radioactive nuclei decays into smaller nuclei by releasing gamma radiation, the mass number remains same.
Answer: The mass of given amount of copper (II) cyanide is 462.4 g
Explanation:
To calculate the number of moles, we use the equation:
We are given:
Moles of copper (II) cyanide = 4 moles
Molar mass of copper (II) cyanide = 115.6 g/mol
Putting values in above equation, we get:
Hence, the mass of given amount of copper (II) cyanide is 462.4 g
Answer:
C. Gas exchange occurs through the placenta.
Explanation:
The fetus is a developing baby in the womb or uterus. The fetus is incapable of performing certain life processes itself and hence, depends on the mother to do them. One of these processes is GAS EXCHANGE. Gas exchange occurs in the fetus via a structure called PLACENTA.
Placenta is a structure that forms in the uterus during pregnancy. It helps the developing fetus supply oxygen and nutrients from the mother and also remove wastes from the fetus back to the mother. The oxygen is taken into the fetus via the PLACENTA while the carbon dioxide (waste product of respiration) is removed via the PLACENTA. Hence, Gas exchange occurs through the placenta.
C=2.41 g/L
m(NaCl)=0.291 g
c=m(NaCl)/v
v=m(NaCl)/c
v=0.291/2.41= 0.1207 L = 120.7 mL
