Поставьте вопросы к выделенным членам предложения 1 sometimes he is sent to petersburg on business. 2 this work will be done tomorrow. 3 some magazines were left for him on the table.

1. Where is he sometimes sent on business?
2. When will this work be done?

Buffer solutions, depending on their composition, are divided into 2 main types:

acidic and basic.

Acid buffering systems are usually formed by a weak inorganic or

organic acid and a salt of the same acid with a strong base.

For example:

1) CH3COOH + CH3COONa - acetate buffer

weak acid salt acid

2) H2CO3 (H2O + CO2) + NaHCO3 - hydrocarbonate or

weak acid salt acid bicarbonate buffer.

Basic buffer systems are formed by weak inorganic or

organic base and a salt of this base with a strong acid. For example:

1) NH3 · H2O (NH4OH) + NH4Cl - ammonia buffer

weak base salt

2) C2H5 – NH2 + C2H5NH3Cl - ethylamine buffer

weak base salt

Basic buffer systems are formed by weak inorganic or

organic base and a salt of this base with a strong acid. For example:

1) NH3 · H2O (NH4OH) + NH4Cl - ammonia buffer

weak base salt

2) C2H5 – NH2 + C2H5NH3Cl - ethylamine buffer

weak base salt.

1. I don’t think John will pass his French exam; he hasn’t studied enough

2. This time next week I will be shopping in Milan.

3. By the end of the month I will have finished this project.

4. When are you going to fly to London? Tomorrow morning.

5. What are you going to buy Fiona for her birthday?

6. Helen and I are going to the cinema tonight.

7. I‘ll close the window.

8. Clark will be driving his new car tomorrow at 12 o’clock.

№ 2

1. Will you pick up Susan from school?

2. Why are you picking at your food like that?

3. You shouldn't pick on younger children.

4. Can you help me pick out a tie to match this shirt?