Упр.5 Appendix 2 Chemistry 2020 ГДЗ Enjoy English 11 класс
a) Complete the texts about the items in the chemistry laboratory. Use the words from the box.
mix, experiments, vertical, quantities, liquid, loss, reactions, convenient, boiling
Test tubes are essential things in a chemistry laboratory. They are used to hold, mix, or heat small (1) … of chemicals. The chemicals may be solid or (2) … Chemists often use test tubes when they perform (3) … and demonstrations.
Test tube holders are used to keep several test tubes in a (4) … position. It is important as some chemical (5) … take time, and the chemists who perform the experiments need several tubes at hand. Clean test tubes are also kept in test tube holders.
Erlenmeyer flask is named after the German chemist Emil Erlenmeyer, who created it in 1860. The conical form and narrow neck of this flask make it very (6) … to mix different liquids. The chemist can just swirl the content of the flask to (7) … it. The narrow neck prevents the content from spilling out.
Erlenmeyer flasks are often used for (8) … liquids. It’s not easy for hot vapors to get out through the narrow neck. A good part of the vapor condenses in the upper part of the flask and gets back to the liquid, reducing its (9) …
b) Work in pairs. Choose one chemistry lab object and explain what it is used for. Use the words and phrases in the box if needed.
LANGUAGE HELP
hold the chemicals; mix the chemicals; heat the chemicals; not to burn the fingers; to avoid injuries; to hold test tubes in a vertical position; condense; evaporate excess water; make a more concentrated solution; to produce solid crystals of the dissolved substance
a)
Test tubes are essential things in a chemistry laboratory. They are used to hold, mix, or heat small quantities of chemicals. The chemicals may be solid or liquid. Chemists often use test tubes when they perform experiments and demonstrations. Test tube holders are used to keep several test tubes in a vertical position. It is important as some chemical reactions take time, and the chemists who perform the experiments need several tubes at hand. Clean test tubes are also kept in test tube holders.
Erlenmeyer flask is named after the German chemist Emil Erlenmeyer, who created it in 1860. The conical form and narrow neck of this flask make it very convenient to mix different liquids. The chemist can just swirl the content of the flask to mix it. The narrow neck prevents the content from spilling out. Erlenmeyer flasks are often used for boiling liquids. It’s not easy for hot vapors to get out through the narrow neck. A good part of the vapor condenses in the upper part of the flask and gets back to the liquid, reducing its loss.
b)
A test tube holder is used to hold test tubes in a vertical position. It helps the chemist not to burn the fingers and to avoid injuries.
