Although birds' eggs appear to be fragile, they are in fact extremely robust. The oval shape applies the same rules of engineering as an arched bridge; the convex surface can withstand considerable pressure without breaking.
Missing question: 0,535 gram of KIO₃ dissolved in 250 mL of de-ionized water to <span>make primary standard solution.
m(</span>KIO₃) = 0,535 g.
V(KIO₃) = 250 mL ÷ 1000 mL/L = 0,25 L.
n(KIO₃) = m(KIO₃) ÷ M(KIO₃).
n(KIO₃) = 0,535 g ÷ 214 g/mol.
n(KIO₃) = 0,0025 mol.
c(KIO₃) = n(KIO₃) ÷ V(KIO₃).
c(KIO₃) = 0,0025 mol ÷ 0,25 L.
c(KIO₃) = 0,01 mol/L = 0,01 M.
Answer:
20 g of CO₂ have 5.47x10²³ oxygen atoms
Explanation:
1 mol of CO₂ has 1 mol of C and 2 moles of O.
Mass / Molar mass = Moles
20 g / 44 g/m = 0.454 moles
In 1 mol we find 2 moles of O
In 0.454 moles of CO₂, we will find ( 0.454 .2) = 0.909 moles
1 mol has _____ 6.02x10²³ atoms
0.909 moles have (0.909 . 6.02x10²³) = 5.47x10²³ atoms
Answer:
-1104 kJ/mol
Explanation:
The change in the enthalpy of a reaction is equal to the difference between: the sum of the enthalpy changes of the bonds broken and the sum of the enthalpy changes of the bonds formed.
The bonds broken correspond to the cleavage of bonds of the reactants, the bonds formed correspond to the bonds of the products:
- we only break oxygen O=O bond, since carbon is not bonded to anything;
- we form two C=O bonds in carbon dioxide.
Therefore, the enthalpy change is calculated by:
