Worksheet Acids and Alkalis [PDF]

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AL REEYADA INTERNATIONAL SCHOOL MAHASEN ARAMCO, AL HASSA, KSA SY 2014 – 2015 2ND TERM SCIENCE 7 WORKSHEET IN ACIDS AND ALKALIS NAME: ________________________ GRADE: _______ ROLL NO.: _____________ DATE: ______________



I. CHOOSE THE MOST SUITABLE ANSWER AND WRITE THE CORRESPONDING LETTER (A, B, C, OR D) IN THE BRACKETS ( PROVIDED. 1



2



Acids are _________. A



sour in taste



C (



sweet in taste )



C than 7



4



B



salty in taste D



bitter in taste



The pH value of an acid is __________. A



3



)



less than 7



B



equal to 7



more than 7 ( )



D



either less than 7 or more



Alkalis are __________. A



sour in taste



C (



sweet in taste )



B



salty in taste D



bitter in taste



Which of the following acids is contained in apples? A



hydrochloric acid



B



citric acid



C (



malic acid )



D



tartaric acid



5 Which of the following generally reacts with acids to form a salt and hydrogen gas?



6



A



alkalis



B



carbonates



C



metals



D



nitrates



(



Which of the following acids is produced in our stomach?



)



A



carbonic acid



C (



hydrochloric acid )



B



sulphuric acid D



nitric acid



7 The acid used in making fertilisers and explosives is ____________. A



hydrochloric acid



B



carbonic acid



C (



sulphuric acid )



D



nitric acid



8 Litmus paper (purple colour) in distilled water when added to an acid changes to



9



A



red



B



green



C



blue



D



purple



(



)



One property of sodium hydroxide is that it ____________.



A turns blue litmus paper red paper blue C (



tastes sour )



B D



turns red litmus



is not reactive



10 Which of the following substances has a pH value of more than 7? A



oxalic acid



B



calcium hydroxide



C



methyl orange



D



hydrogen gas



(



) 11 When an indicator is added to solutions of different pH values, it should show a change in ___________. A



colour



B



state



C



volume



D



smell



) 12 When phenolphthalein is added to an alkaline solution, it turns __________. A



pink



B



colourless



(



C (



white )



D



green



13 Alkalis can be used for the following purpose except for _________. A



making soaps



B



C



neutralizing acidic soil D ( )



manufacturing salts making explosives



14 What will happen to the pH value of an alkali when acid is slowly added to it? A



it increases



B



it decreases



C it remains the same decreases ( )



D



it increases and then



15 HCl, H2SO4, HNO3 are the chemical formulae of some acids. The element that can be found in all acids is __________. A



hydrogen



C



oxygen



B D



nitrogen



sulphur



(



)



II. SHORT ANSWER QUESTIONS 1. State whether each of the following is acidic or alkaline. a. Grapes _________________________ b. Soap _________________________ c. Solutions in car battery _________________________ d. Vinegar _________________________ e. Bee sting _________________________ 2. Name three different acids that can be found in fruits. _____________________________________________________________________ _____________________________________________________________________ 3. What should be done immediately if an acid or an alkali gets into a person’s mouth? _____________________________________________________________________ _____________________________________________________________________ 4. The table shows the colour of different indicators when tested with different substances P, Q, R and S. Substance P Q



Colour of litmus Colour of paper phenolphthalein Blue Colourless Red Colourless



Colour of methyl orange Yellow Red



R Blue Pink Yellow S Red Colourless Yellow Arrange the substances according to their pH values, from the lowest pH to the highest pH. _____________________________________________________________________ 5. Complete the following equations. A Iron + Sulphuric acid  _____________________ + ____________________ B Calcium carbonate + Hydrochloric acid  _____________________ + _____________________ + ___________________________ C Zinc + ___________________  Zinc chloride + _____________________ III. STRUCTURED QUESTIONS. 1. State the general properties of acids. _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 2. Give (5) examples of acids and their uses. _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 3. State the general properties of alkalis. _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 4. Give (5) examples of alkalis and their uses. _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________



5. Describe briefly what happens to a mixture of alkali and ammonium salt when the mixture is heated. _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Note: Bring the worksheet on February 9, 2015 Monday.