BYJUS SCIENCE GRADE 7 CHEMISTRY Flashcards
When does a reaction occur
When chemicals come together a reaction occurs
The chemicals that participate is a reaction are called
REACTANTS
The final outcome of a reaction is a
PRODUCT
What is a catalyst
The stuff that helps the chemical change and speeds up the reaction
The original colour of the Statue of Liberty was
Brown
The present colour of the Statue of Liberty is
Green
Why has the colour of the statue of the Statue of Liberty changed from Brown to Green
Because of Acid Base reactions
Why has the colour of the Taj mahal changed from the original White to the present Cream
The TM is made up of chemicals that conatins a base and when it reacts with rain that is mildly acidic it changes colour
Lemons are an alkali
True or false
False
Lemons are acidic
Soap has a base
True or False
True
When a substance has more of an acid it is known as
Acidic
Everything that alkaline is a base
True or False
True
Everything that a base is alkaline
True or False
False
Are Amino acids actually acids
No. Even though it contains the word acid it has an acidic part and a basic part.
Most chemical processes in a living organisms occur as acid base reactions.
True or False
True
The basic unit of Proteins is
Amino Acids
The basic unit of fats is
Fatty acids
How is wine made
Fermentation of fruits
The most common acids outside the human body and industrially made are
- Hydrochloric acid HCl
- Sulphuric Acid
- Nitric acid
In ancient times all sour substances was considered to be
Acids
What is the common name of Table salt aka common salt
Sodium Chloride Nacl
What are vegetable dyes
Coloured extracts of certain plants
Name two Natural acids
Citric acid
acetic acid
What is Aqua Regia
It is a mixture of Hydrochloric acid and Nitric acid
What is the importance of Aqua Regia
It can dissolve gold
Bases help to Neutralize acids
True or False
True
Acids have a corrosive property
True or False
True
From where is the world Alkali derived
From the Arabic word Al-qualiy which means ashes
What is an alkali
Its a Base that can be dissolved in water
Who is an Alchemist
A person who tries to convert metal to Gold
Who discovered the element Phosphorous
Hennig Brand
He boiled 60 buckets of urine and accidently ended up discovering Phosphorous
Phosphorous is also found inside bones
True or False
True
What is an EXOTHERMIC REACTION
A reaction that generates Heat
Potassium Hydroxide KOH combines with Nitric acid and form an important salt called
Saltpetre
Quantitative measure of the acidity or basicity of aqueous or other liquid solutions
pH
What does pH actually stand for
Hydrogen Potentials
the pH scale ranges from
1 to 14
The highly acidic solutions will have a ———— pH
Lower pH
The two indicators of acid base chemistry are
- Visual Indicators
- Olfactory Indicators
The Litmus is an extract of which plant
Lichen
Who first used the Litmus paper
Spanish Physician Arnaldus De Villa Nova
Litmus by default is what kind of a dye
Blue dye
Red cabbage contains a pigment called
Anthocyanin
In an acidic solution the Anthocyanin changes colour to
Pink/Red
In a mildly alkaline solution the Anthocyanin changes colour to
Purplish to green
In a very alkaline solution the anthocyanin changes colour to
Yellow
ABRACADABRA
Acid turns blue litmus Red
What is an aqueous solution
Water containing solution
What is a GLAUBERS REACTION
When an acid and a base come together a salt is created and heat is given out
What is an ENDOTHERMIC REACTION
A reaction where heat is absorbed
What is NEUTRALIZATION
The chemical reaction that involves bases nullifying acids and creating water and salts
The yellow chemical found in Turmeric is
Curcumin
What colour does turmeric change in an alkaline medium
Red
List four properties of an Acid
- Sharp and sour taste
- Corrosive action on metals
- Turns blue vegetable dye red
- Reduce in the acid property when mixed with a base
List Three properties of bases
- Soapy to touch and bitter in tatse
- Turns red vegetable dyes to blue
- Reduce in the base property when mixed with acid
What is CHEMICAL EQUIVALENCE
The ability of a fixed quantity of acid to neutralize a fixed quantity of base
What is the chemical name of Quick lime
Calcium oxide
What is the chemical name of Slaked lime
Calcium Hydroxide
Where is quick lime and slaked lime used
As it is a base it is put in acidic soil to help plants grow
Remember PAM
What is the usefulness of
Phosphate Salts
Ammonium Salts
Metal Salts
- Fertilizers
- Neutralize acidic rivers and protect aquatic life
Where is citric acid used
To flavour drinks
What are the two uses of table salt
- Flavouring food
- Preserving food
Uses of Hydrochloric and phosphoric acid
Are components of Lime scale removers
Salts are used to produce colours in fireworks
True or False
True
What colour does Sodium Chloride impart to a fire work
Yellow
What colour does calcium Chloride give to a fire work
Red
Name the chemical that gives a Green or Blue flame to a fire work
Copper chloride
The chemical name of Baking powder
Sodium Bicarbonate
Name the strong acid found in gastric juice
Hydrochloric acid HCL
The Hydrochloric acid found in gastric juice is usd to break down which nutrient
Protein
Stron Alkalis can be as irritating as Srtong acids
True or False
True
Name a strong Alkali used in Bleach
Sodium Hydroxide
NaOH
Name two strong Alkalis
- Sodium Hydroxide NaOH
- Potassium Hydroxide KOH
Where is potassium hydroxide used
In alkaline batteries
Name a very common Alkali
Sodium Hydroxide
Is the drug asprin an acid
Yes
Acetylsalicylic acid
Can icids be used to clean Rusty/corroded surfaces
Yes
Acids react with metal oxide
What is Lime Scale
It is Lime stone like deposits on ceramic surfaces
What is BRINE
A highly concentrated solution of common salt
What is Electrolysis
the process of using electricity to split water into hydrogen and oxygen
How is Sodium Hydroxide NaOH produced on a large scale in Industries
Electrolysis of Brine
The atmosphere of Venus is made up of which acid
Sulphuric acid
Plastics reacts very fast with acids
True or False
False
Plastics dont usually react with acids
Why are water pipes, drain pipes and gutters made of plastic
Because plastics do not react with acids