Edexcel GCSE chemistry C1b.8

L________ - flexible, confortable and strong. Reduces a____ resistance to improve performance speed. Stretches more than r______ but is more resistant.

Thinsulate  - made from p____________ fibres, very thing (just 1/100th human h_____). I_____________ the body by trapping lots of a______. R__________ body heat back in towards the body.

Carbon fibres - stiff but not easy to s________. Can be moulded by setting them in p__________ and are 4x stiffer than the finest s________ (weight for weight).

Smart memory a________ - atoms are in a fixed pattern, which they return to when h____________.

Kevlar - ___ x stronger than steel and can be woven into c_______.  Use in lightweight b_______ p______ v_______. String because it has long m___________ which make chemical b______ between them.  Also used for skis and b______ pads.

G__________ - invented to solve the problem of rain macs making people sweaty. It has a plastic layer with millions of m_______________ holes sandwiched between layers of f_______. Tiny water molecules in water vapour from s_______ is small enough to fit through the holes, but raindrops are too l________ to get in.  The b____________ stops people getting sweaty but also stops them from getting wet from the rain.

Many new materials have been discovered by a____________.  The glue on post-its was discovered when a Scientist was trying to make a strong adhesive but made a weak one instead.

Teflon - a 'slippery' p_________ which is used as a non-stick coating on frying pans, To coat fibres in clothes so that d_____ and stains can't stick.

A nanometre is one b_________ of a metre.

N_____________ range from 10 - 100 nanometres and are too small to see even with a microscope. Their size gives them some very useful p___________.  Clear sunblock uses nanotechnology.  The particles are too small to see but still block the _____ rays.

Nanocomposites - nanoparticles added to other materials to improve their p___________.

Nanotubes - sheets of c_______ rolled up to make tubes.

N_________ - nanosized machines which may be used in future to do many jobs (i.e. cleaning, medical treatments etc). Many people are worried about the potential dangers of nanobots harming the environment or the body.

Beer - ferments a weak sugar made from boiling b_________ in water. Yeast (a simple, single-celled f_______) is added and the solution is kept at 37oc.  The yeast feeds on the sugar and r____________:

                  Sugar --> A_________ + C___________ D____________

W______ is made in the same way, except we use g______ juice instead of barley. Wine is usually stronger than beer because there is _______ sugar in grape juice than in barley.

Yeast breaks the sugar down into almost equal amount of a________ and carbon dioxide.  The carbon dioxide bubbles out but the alcohol stays in solution. Monitoring the amount of gas produced shows how the f___________ process is progressing.

Adding more sugar will not necessarily make more alcohol as the alcohol is t______, at about 15% it kills the y______ cells.  Alcohol can be made more concentrated by d____________.  Anything above ___% would be dangerous to drink.

E__________ is the alcohol in alcoholic drinks. It makes people more chatty and less self-conscious. Small amounts can actually help maintain h______ in adults.

This drug effects the b________ and b______. Large amounts can be harmful and can make users emotional, agressive or v_________. B_________ and co-ordination are lost, vomitting is common, people sometimes faint when b______ pressure is affected. Very large amounts can kill people.

One unit = a small glass of w_____, half a pint of b____, a single pub measure of s________ or 2/3 of a bottle of a_________.

Recommended daily limits are ______ units for men, or ____ units for women.

Hangover is often caused by d___________ (alcohol makes the body pass more urine and loose more water than is taken in when drinking).  H___________ is caused by the brain shrinking away from the skull.  Irregular h______ beat can be caused by the loss of important salts in the urine. The waste products produced when alcohol is broken down by the l_______ upset the body chemistry.

Excessive drinking can cause h______ disease, stroke, l______ damage and some types of c________.

B_______ drinking is a big problem in todays society.  It costs the taxpayer a lot of money as the p_______ are kept busy by the poor behaviour due to exceesive drinking, and the NHS has to cope with increased number of i_________ and increasing numbers of alcohol related illnesses.

M__________ cause food to go 'off'. Some simply make food taste ad but others can cause i________ or even death. Many of these organisms need w________ and o_________ to grow and reproduce. P_________ packaging simply covers the food, stopping the microbes growing by stoppin either of these substances getting to the food.

We can remove all w_______ by dehdrating the food (i.e. cup-a-soup)

Active packaging controls or c_________ the atmosphere around the food.

We can remove the o___________ from the packaging and replace it with other gases such as carbon dioxide or n_________. The stops microbes growing but also stops fats going r_______.

Intelligent packaging tells the consumers something about the product. i.e a dot that changes colour if the food has not been kept below the right t__________, or packaging that canges c_______ when fruit is ripe and ready to eat.

Emulsions are mixtures of oil and w______, which normally would not mix.  An e_____________ is added which holds the oil and water together so they cannot s___________.

The e_____________ in mayonnaise is lecithin, found in e__ y_____.

The hydrophobic (water h________) end of the emulsifier attaches to the oil and the h______________ (water loving) end of the emulsifier attaches to the water molecule holding the two together.

Soaps and detergents work in a similar way. Dirt stuck in place by grease or oil can be removed when the hydrophobic ends of the detergent attach to the grease and the hydrophillic ends pull the grease into the water leaving the clothes clean.