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Lesmahagow High School S3 Crop Chemistry

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Lesmahagow High School S3 BGE Chemistry

Chemistry in Society

Crop Chemistry

Through investigations and based on experimental evidence, I can explain the use of different types of chemicals in agriculture and their alternatives and can evaluate their potential impact on the world’s food production. SCN 3-03a Through investigating the nitrogen cycle and evaluating results from practical experiments, I can suggest a design for a fertiliser, taking account of its environmental impact. SCN 4-03a Plant nutrients, and elements, natural and synthetic fertilisers

National 4


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Learning Outcomes


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Carbohydrates

Carbohydrates are natural compounds containing C, H and O. Carbon, hydrogen and oxygen are non-metal elements and so carbohydrates are made up of molecules with atoms joined by covalent bonds. All carbohydrates include two hydrogen atoms for every one oxygen atom.

Complete the table:

Name Formula Carbohydrate (yes or no)

glucose C6H12O6

acetone C3H6O

carbon monoxide CO

hexene C6H12

sucrose C12H22O11

water H2O

alcohol C2H5OH


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Testing 2 types of carbohydrates – starch and sugar

(glucose)

Aim: To find out how to test for starch solution and for glucose solution. Method: (Draw a labelled diagram)

Results:

Conclusion: Starch We can test to see if a food has starch in it by using I__________ S__________. This changes from an o_________ / b___________ to a b__________ /b__________ colour.

Solutions Iodine solution Benedict's solution

Water

Glucose

Starch


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Glucose We can test to see if a food has glucose in it by using B__________ S__________. This changes from a b___________ to an o__________ colour. Digestion of Carbohydrates Starch is a very large molecule and is made up of lots of small glucose molecules joined together. Our bodies can break starch down into glucose.

Hydrolysis Starch is made in plants by joining ________ molecules together in very long chains, several thousand long, by a _____________ reaction. When we eat starch in our food it is too big a molecule for our bodies to use, so it is broken down back into ____________, by enzymes in our ____________ system. The glucose molecules can then pass through our intestine into the bloodstream. This reaction is called _____________.


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Equation for hydrolysis during digestion: Respiration In plants and animals, food is processed to get the energy out for our bodies to use. This is called ________________. In our bodies, ____________ from our breathing is used in our cells to react with the glucose:

C6H12O6+_____ → ___ + ___ Because oxygen from the air is used, this is called __________ respiration. Fermentation If carbohydrate is in contact with the yeast fungus, __________ in the yeast can use the glucose to make _________ and gain energy. This is called ______________.

C6H12O6 → CO2 + C2H5OH Glucose → Carbon Dioxide + Ethanol

Because oxygen is not needed in this reaction, this is called ____________ _______________.

(C6H10O5)n + H20 → n C6H12O6

starch + water → glucose


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In order for fermentation to occur yeast is used which contains an enzyme, __________. Enzymes are biological catalysts. The process must be carried out in warm conditions but not above 50oC. Even in _________ conditions the percentage of alcohol is only ____%. In order to produce alcoholic drinks with an alcohol percentage greater than 15%, _____________ is used. Distillation Ethanol is made more concentrated by separating it from water, which has a higher boiling point. (Label the diagram)


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Alcoholic Drinks There are a wide range of drinks that contain _____________ including wine, spirits, beer and cider. Whether it be grapes for wine, barley for beer and whisky or even rice and potatoes for sake and vodka, the ____________ within them is converted to ______________. Complete the table:

Alcoholic drink Source of carbohydrate

Beer

Wine

Whisky

Vodka

Sake

Cider

Gin

As previously mentioned, the most common alcohol is ethanol (found in alcoholic drinks), the amount of ethanol in different types of drinks can vary. Most labels show the % _____________ of ethanol, but many now show how many _______ the drink contains. __________are used to show the drinker how much alcohol they are consuming by the ___________, can or bottle.


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1 unit of alcohol is _____cm3 of pure ________. Unit Calculation ABV – Alcohol by Volume ( strength of the drink %) No.of units = Strength (ABV) x Volume(ml) 1000 Becks = 4% ABV (275ml bottle) No. of units = 4 x 275 = 1.1 1000 Wine = 12% ABV (750ml bottle) No of units = 12 x 750 = 9 1000 Try the examples below: 1. Units in a 750ml bottle of wine at 11% ABV 2. Units in a 250ml bottle of cider at 6% ABV


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Drugs and Medicines

Products from Plants

Label the diagram! Oils can be extracted from fruits and other plants by steam distillation.

Orange lemon /lime peel

5ml


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Extraction of Essential Oil from______________ Aim: _______________________________________________

_______________________________________________

_______________________________________________

Method: Results: _______________________________________________

_______________________________________________

_______________________________________________

Conclusion: _______________________________________________

_______________________________________________

Evaluation

_______________________________________________

_______________________________________________

_______________________________________________


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Making Soap

Aim: _______________________________________________

_______________________________________________

_______________________________________________

Method:

Results: _______________________________________________

_______________________________________________

_______________________________________________

Conclusion: _______________________________________________

_______________________________________________

Evaluation

_______________________________________________

_______________________________________________

_______________________________________________


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Fertlisers and Plant Growth

Feeding People

The world _______ is increasing rapidly and this has ________ the demand for _______. Modern __________ methods, especially using ___________, have enabled ________ food to be grown to feed the entire world Despite this people still go hungry due to politics and wars.

Feeding Plants Plants get the __________ they require from _________. For good __________ plants need many elements but the most important are _________, __________ and __________. (N, P and __) A _______________ is a ____________ which contains one or more of the ______ elements nitrogen, phosphorus and potassium.

mill

ions

of

peop

le

0

1000

2000

3000

4000

5000

6000

year1700 1750 1800 1850 1900 1950 2000


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Most fertiliser bags give information about the amounts of these three elements present This is called the NPK system

Properties of Fertilisers Plants need to get their _________ from the soil, through their ________. The ________ from the soil is taken in through the roots, so _________ must __________ in water – they need to be __________.

Plant root

Nutrients in soil


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Testing Fertilisers Aim: To test the solubility of a set of fertilisers Method:

1. Half a spatula of each fertiliser was added to separate test tubes. 2. Each test tube was stoppered and shaken in turn to see if the fertiliser was soluble or not. Results

Conclusion __________________________________________

__________________________________________

_________________________________________

Fertiliser Very soluble

Name Formula N,P or K (y/n)

ammonium nitrate

ammonium phosphate

ammonium sulphate

calcium phosphate

potassium chloride

potassium nitrate

NH4NO3

(NH4)3PO4

(NH4)2SO4

Ca3(PO4)2

KCl

KNO3


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Other Chemicals (Pesticides) A _________ is a term used to describe all products which control pests. These pests include _______ (insecticides), weeds (____________), plant diseases (____________) and mammals. Advantages of pesticides Farmers crops are not ________ or destroyed by pests. This means they will have more to sell and __________ their profits. Disadvantages of pesticides Some pesticides have been found to _________harm humans and other mammals as well as the pest. This is because the __________ build up in the _______ chain. DDT is an example of a pesticide. It was first made in the 1940’s and was used to combat serious diseases such as malaria, typhus and other diseases that are spread by insects. Farmers also used it to control pests that were eating their crops. However in 1972 it was found that DDT posed a serious danger to human health and wildlife. Natural Fertilisers ______ fertilisers include substances like ______, compost or ______ meal, which are _______ products but are naturally high in _______, phosphorus and _______.


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Making Man Made Fertilisers Ammonium sulfate is an example of a synthetic or man made fertiliser. You will make some in the lab. Take a note below of how you did it:

_____________________________________________

_____________________________________________

_____________________________________________

_____________________________________________

_____________________________________________


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The Nitrogen Cycle One of the most important ___________ is nitrogen. This is needed by all _________. In nature it needs to be converted from nitrogen ________ to nitrogen _________ that plants need. These are called _________ and nitrites.

Problems with Fertilisers _________ fertilisers are necessary because we remove _________ from the soil when we _________ crops. These would normally be ________when plants die and __________. However, ________ of fertilisers can lead to ____ _______nutrient in our _________, leading to problems like ________ __________ .

Atmospheric Nitrogen

in soil

Any Plant

Plant Protein Animal Protein

Animal nutrition

Animal nutrition

Nitrites (NO2-)

Nitrates (NO3-)

Denitrfyingbacteria in soil

Death

Lightning strike forms Nitrogen dioxide

Acid Rain

Nitrogen fixing by bacteria in some plants

Denitrfyingbacteria in soil

Decomposers


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Fertiliser poster research

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Lesmahagow High School Rates of Reactions

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Learning Statements


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Crop Chemistry - Glossary

chemistry in society crop chemistry - lesmahagow … in society crop chemistry through...

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