Zadania z chemii IB SL

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Filtry i umiejętności

Outline why the scientific model of the atom has been modified several times since it was first proposed.

średnie (szac.)

Which electron transition in a hydrogen atom emits radiation with the longest wavelength? A. $n = 2$ to $n = 1$ B. $n = 3$ to $n = 2$ C. $n = 4$ to $n = 3$ D. $n = 1$ to $n = 4$

Sketch, on the axes, the graphs of the time for complete reaction against the mass of metal that you would expect for sodium and for potassium. Label each line.

Suggest why the times measured for equal masses of the two metals are not a valid basis for comparing their reactivity.

When sodium burns in excess oxygen, the main product is sodium peroxide, $\ce{Na2O2}$ . Determine the percentage covalent character and the bonding type in sodium peroxide using sections 9 and 17 of the data booklet.

Sodium peroxide, $\ce{Na2O2}$ , contains the peroxide ion. Draw the Lewis formula of this anion.

A sealed flask contains 8.0 g of helium and 120 g of argon. What is the ratio of the number of atoms of argon to the number of atoms of helium in the flask? A. 0.067 B. 0.67 C. 1.5 D. 15

Write an equation for the complete combustion of $\ce{C19H40}$ .

The enthalpy of combustion of $\ce{C19H40}$ is $-12\,660\ \mathrm{kJ\,mol^{-1}}$ . (i) Calculate the maximum energy released when 1.50 g of $\ce{C19H40}$ is burned completely. (ii) Determine the maximum temperature increase when $400.0\ \mathrm{cm^3}$ of water…

Explain why a fuel produced from recently grown plants (a biofuel) contributes less to climate change than a fossil fuel.