Zadania z chemii IB HL

(i) Determine the molecular formula and the empirical formula of cresolphthalein. (ii) A simplified infrared (IR) spectrum of cresolphthalein is shown below. State the bonds responsible for the absorptions labelled P, Q and R. Use section 20 of the data…

Which of the following could be the empirical formula of a compound with $M_\mathrm{r} = 70$? I. $\ce{CH2}$ II. $\ce{C4H6O}$ III. $\ce{C5H10}$ A. I and II only B. I and III only C. II and III only D. I, II and III

(i) Suggest a reason for the slight change in colour observed after the night in the oven. (ii) Suggest how the students could make sure that dehydration in the crucible was complete. (iii) Suggest one way in which the students could reduce the effect of…

Each student used a different mass of the hydrated salt. The results of the whole class are shown below ($M_r$ of $\ce{H2O}$ = 18.02). Student Mass of $\ce{CuSO4 * XH2O}$ / g Mass of $\ce{CuSO4}$ / g Loss in mass / g Amount of $\ce{CuSO4}$ / mol Amount of…

Calculate the percentage by mass of hydrogen in compound Y, giving your answer to four significant figures. Use section 7 of the data booklet.

What is the empirical formula of a compound with the following composition by mass? Element C H O Percentage by mass 54.5 % 9.1 % 36.4 % A. $\ce{C6HO4}$ B. $\ce{C4H8O}$ C. $\ce{C2H4O}$ D. $\ce{C4H8O2}$

When 3.71 g of Z was burned completely in excess oxygen, 8.81 g of carbon dioxide and 4.51 g of water were collected. Determine the empirical formula of Z. Use sections 1 and 7 of the data booklet.

4.81 g of sulfur was heated in a stream of chlorine gas until the reaction was complete. The mass of the chloride produced was 10.13 g. (i) Calculate how many atoms are present in this 4.81 g sample of sulfur. Use sections 2 and 7 of the data booklet. (ii)…

Determine the empirical formula of HA from the percentage composition.