In water, d-glucose exists as an equilibrium mixture of three different structures, an open chain structure (present in trace amounts) and two chair conformational structures, one present in a ~64% amount and the other in a 36% amount. draw each of the structures in question and comment on why there is a greater amount of one cyclic structure present over the other. also explain why there is so little of the open chain structure present in the mixture. (i) (12 mark in relation to the three structures drawn in (i) above, explain the (5 mark (ii) phenonomen "mutarotation of d-glucose". in your answer it is necessary to quote appropriate specific rotation values. (8 mar in relation to the two cyclic structures you have drawn, explain (iii) the terms diastereomers; anomers; heterocycles; chiral centres reducing sugars. q6. answer all parts.

n has four pairs of electrons in the valence shell, electrons repel one another ,n has 7 protons in its nucleus, and since n has 7 protons, it must fill the second shell, giving it 4 pairs of electrons. the electrons form 3 bonds and 1 lone pair of electrons. each pair of electrons repels the other pairs, so they are equally far apart.

so all of the above

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

> b takes place in the gas phase in an isothermal tubular reactor. the feed is one mole of a per one mole of c, an inert. the entering temperature and pressure are 427°c and 10 atm, respectively. the gas constant r = 0.08206 atm · l/mol · k.