Recent questions tagged class 7

What do the letters pH stand for?

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Petroleum, gasoline, kerosene, diesel, paraffin wax are yielded on fractional distillation of

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Name the chemical used to test the presence of $CO_2$ in exhaled air.

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Washing soda is the common name for

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In the manufacture of safety matches, which of the following materials are used to coat the two sides of match boxes? 1. Yellow phosphorus 2. Glue 3. Glass powder 4. Red phosphorus

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A solute disappears when it is added to a

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Medicinal drugs are bitter in taste hence they are added with

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A chemical change could best be demonstrated by

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Water is neither acidic nor alkaline because

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To desalinate water technique used is

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Which of the following is a non metal that remains liquid at room temperature?

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The hardest substance available on earth is

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The inert gas which is substituted for nitrogen in the air used by deep sea divers for breathing, is

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Which is the first thing that would happen if a plant could NOT obtain carbon dioxide?

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Low densities, low melting and boiling point and poor conductivity is found in

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In a comparison with a gold atom and hydrogen atom, gold atom is

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Which of the following causes the rusting of iron? a)Oxidation b)Reduction c)Chemical reaction with oxygen d)Chemical reaction with CO

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What are the most common elements in the human body?

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Which of the following is not produced if you mix vinegar (an acid) and sodium bicarbonate (an alkali, or base) together?

asked Aug 11, 2017 by meena.p

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Which of the following has the highest pH value?

asked Aug 10, 2017 by meena.p

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Which of the following is the newest element to be discovered and synthesised?

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Chemical change does not take place in case of?

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Which of the following statements is/are true? A. The process of oxidation leads to a gain of electrons. B. The process of oxidation leads to a Toss of electrons. C. The process of reduction leads to a gain of electrons. D. The process of reduction leads to a loss of electron

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What is the percentage of $CO_2$ in the exhaled air?

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Stainless steel pans are provided with copper bottom because

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Some acids react with many materials and burn skin if they come in contact they are

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Haphazard movement of particles suspended in a liquid or gas caused by bombardment of particles by molecules of medium is

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At room temperature, most elements are in which phase of matter?

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Salt, sugar, chalk, sand are all

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Nitric acid combines with oxygen to produce brown fumes of

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When a solid substance is heated, individual molecules

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On a hot day, a glass containing ice water slowly collects liquid on the outside of the glass. Which statement best explains where this liquid come from?

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A group of students predicts that folding an index card into a different shape will result in a chemical change. Which step of the scientific process is this?

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Which gas in the atmosphere protects us from harmful ultraviolet radiations?

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To study changes that occur during photosynthesis

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To trace path of phosphorus, isotope of phosphorus is added to fertilizers. isotope is

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Study the given set up of an experiment . you will observe that

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A separation technique which uses a fractionating column to separate different liquid components in a mixture with different boiling points by heating mixture is called

asked Aug 9, 2017 by meena.p

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The temperature at which no more energy can be removed from matter is called

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Acids are found in many common chemicals, including foods. Acids taste:

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The effect of sting of an ant can be neutralised by rubbing with

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In hydroponics, plant's roots are immersed in solution of dissolved

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When fizzy drinks are made by adding compressed carbon dioxide acid is formed by mixing which is

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If mass of a substance will be lowered its density will be

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Element which is non-metal and is found on right side of periodic table is

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When iron and Sulphur are mixed together at room temperature there is lack of

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A large amount of heat is produced in power plants while energy is released which turns

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Which gas is produced when sludge is digested?

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An iron weight at $45$ degree celcius is dipped in a bucket containing water at $45$ degree celcius . The heat will

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The densest element so far is

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