We are given
0.2 M HCHO2 which is formic acid, a weak acid
and
0.15 M NaCHO2 which is a salt which can be formed by reacting HCHO2 and NaOH
The mixture of the two results to a basic buffer solution
To get the pH of a base buffer, we use the formula
pH = 14 - pOH = 14 - (pKa - log [salt]/[base])
We need the pKa of HCO2
From, literature, pKa = 1.77 x 10^-4
Substituting into the equation
pH = 14 - (1.77 x 10^-4 - log 0.15/0.2)
pH = 13.87
So, the pH of the buffer solution is 13.87
A pH of greater than 7 indicates that the solution is basic and a pH close to 14 indicates high alkalinity. This is due to the buffering effect of the salt on the base.
I would say mass lost by nuclear collisions. The mass defect is the mass difference between the mass of an atomic nucleus and the sum of the mass of its constituent particles. It equals the energy given off in the formation of the nucleus.
Now ,
C + O2 → CO2
According to above equation, 1 mole of carbon reacts with one mole of oxygen to produce one mole of carbon dioxide.Thus this implies that 12 g of carbon reacts with 32 g of O2 to produce 44 g of CO2.
No of moles = mass of the substance/molecular mass of the substance.
In this case 1.2 g of carbon reacts with "x "g of O2 to produce 4.4 g of CO2.
No of moles of carbon in this case = 1.2÷ 12 = 0.1 moles.
No of moles of carbon dioxide formed = 4.4÷44 =0.1 moles
Thus already discussed above, 1 mole of carbon reacts with 1 mole of oxygen to produce 1 mole of carbon dioxide. Hence to produce 0.1 mole of CO2 ,0.1 mole of carbon needs to react with 0.1 mole of oxygen.
Also number of moles of O2 = mass of O2÷ molar mass of O2
Substituting number of moles of O2 as 0.1 we get
mass of O2(x) = Number of moles of O2 × Molar mass of O2
Mass of O2 (x) = 0.1 × 32= 3.2 g
Thus mass of 3.2 g O2 reacts with 1.2 g of CO2 to produce 4.4 g of CO2.
Answer:
B) C3H3O and C6H6O2
Explanation:
Given data:
Molar mass of compound = 100 g/mol
Percentage of hydrogen = 5.45%
Percentage of carbon = 65.45%
Percentage of oxygen = 29.09%
Empirical formula = ?
Molecular formula = ?
Solution:
Number of gram atoms of H = 5.45 / 1.01 = 5.4
Number of gram atoms of O = 29.09/ 16 = 1.8
Number of gram atoms of C = 65.45 / 12 = 5.5
Atomic ratio:
C : H : O
5.5/1.8 : 5.4/1.8 : 1.8/1.8
3 : 3 : 1
C : H : O = 3 : 3 : 1
Empirical formula is C₃H₃O.
Molecular formula:
Molecular formula = n (empirical formula)
n = molar mass of compound / empirical formula mass
Empirical formula mass = 12×3 + 1.01 ×3 + 16×1 = 55.03
n = 100 / 5503
n = 2
Molecular formula = n (empirical formula)
Molecular formula = 2 (C₃H₃O)
Molecular formula = C₆H₆O₂
Answer:
1) conduction
2) Radiation
Explanation:
Conduction is a mode of heat transfer by which heat energy is transferred through a material, the average position of the particles of the material remaining the same.
Radiation is a process of heat transfer by which heat is transferred from a hotter to a cooler point without any intervening medium.
The pan used to fry the egg is a conductor of heat hence heat can pass through it by conduction thereby enabling the eggs to cook.
Heat can travel without an intervening medium hence Zoe feels hot near the stove. This ability of the heat to travel without an intervening medium is called radiation.
