Classify the following as pure substances or mixture. (a) ethyl alcohol (b) oxygen (c) carbon (d) distilled water(e) blood (f) steel
**Pure substance – ethyl alcohol, oxygen, carbon, distilled water mixture – blood, steel**
pure substances are made up of same type of particles or atoms. all the elements and compounds are pure substances because they contain the same kinds of particles. examples: hydrogen, carbon dioxide the right option is d) pure we are being asked to classify the following reactions based on the following categories:combination/synthesis → multiple reactants combine to form a single productw/o change in oxidation numbersa + b → abdecomposition →reactant splits into multiple products with no change in oxidation numbersab → a + bcombustion reaction: reaction with oxygen that produces carbon dioxide and waterhydrocarbon + o2 → co2 + h2osingle displacement →single element displaces another element in a compoundab + c → ac + b[readmore]let’s analyze the given reactionsa. fe2(co3)2 (s) → fe2o3(s) + 2co2(g) break down of fe2(co3)2(s) to its component ions → decomposition reactionanswer: this is a decomposition reaction.b. 2 c6h11oh(l) + 17 o2(g) → 12co2 (g) + 12h2o(l) reaction with oxygen that produces carbon dioxide and water → combustion reactionanswer: this is a combustion reaction.c. p4o10(s) + 6h2o(l) → 4h3po4(aq) two or more substances combine to form a single compound → combination reactionanswer: this is a combination reaction.d. 2c(s) + mno2(s) → mn(s) + 2co(g) substitute one element for another element in a compound →single-displacement reaction answer: this is a single-displacement reactione. 2naclo3 (s) → 2nacl(s) + 3o2(g)break down of compound into its simpler substances → decomposition reactionanswer: this is a decomposition reaction solid + liquid mixture : sand and water, charcoal and water. hint: at first think about the structure of ester so that you are able to draw the structure for a given molecular formula. the structure of ester is $r - co - o - r'$.complete answer:an ester is a chemical compound derived from an acid in which at least one –oh group is replaced by an $ - o - $ alkyl group. esters are generally derived from substitution reactions of a carboxylic acid and an alcohol which is also known as an esterification reaction. from the given molecular formula we can draw only two structures of esters. they are ethyl formate and methyl acetate. their structures are $h - co - o - c{h\_2} - c{h\_3}$ and $c{h\_3} - co - o - c{h\_3}$.additional information:esterification is the process of combining carboxylic acid and alcohol to give at least one ester and water.$r - co - oh + r - oh \rightleftharpoons r - co - o - r' + {h\_2}o$in the above reaction, the forward reaction gives us esterification and the backward reaction gives us hydrolysis of the ester. the hydrolysis of esters in the presence of alkalis such as potassium hydroxide (lye) or sodium, a reaction called saponification which is utilized in the preparation of soaps from fats and oils and is also used for the quantitative estimation of esters.note:esters are common in organic chemistry and biological materials, and often have a pleasant characteristic, fruity odor. this leads to their extensive use in the fragrance and flavor industry. ester bonds are also found in many polymers. hydrocarbons are the compounds of hydrogen and carbon. they are the simplest of all the organic compounds.hydrocarbons are of two types:(i) organic (ii) inorganic hey there! as answered previously:-
crystallization is the process of slow precipitation of solid
crystals of a substance from a concentrated homogeneous solution it
is basically a separation method in which a substance is
transferred from the liquid (i e solution) phase to the solid state
the substance is thus obtained in pure crystalline form and has no
impurity it is used by chemists for the purification of solid
substances
following is an example of using crystallization to obtain pure
copper sulphate from an impure sample
1) take a small amount (5 g) of an impure sample of copper
sulphate in a china dish
2) dissolve the sample in 10 ml of water (we basically have to
use minimum amount of water in order to prepare a saturated
solution)
3) then, filter it to remove impurities
4) evaporate the filtrate on a water bath till small crystals
are formed indicating that a concentrated solution has been
obtained
5) after this, cover the solution with a filter paper and leave
it undisturbed at room temperature for the rest of the day
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it will be observed that crystals of pure copper sulphate are
obtained and the impurities are left behind in the solution according to ncert answer would be option (1)and

but according to general chemistry answer would be (3)andoption 1)and





option 2)andoption 3)andoption 4)and cao we are going to do the following steps:step 1: determine the classification of the compoundstep 2: write the formula of the compound[readmore]step 1: determine the classification of the compoundrecall the definition of the following:ionic compound - usually made up of a metal and a non-metalcovalent compound - composed of more than one nonmetal togetheracid - substance whose molecules yield hydrogen ions (h+) when dissolved in waterhydrate - substance that contains water or its constituent elementsfor cobaltic iodidecobaltic – metaliodide – nonmetalmetal + nonmetal = ionicstep 2: write the formula of the compoundthe rules for naming ionic compounds are as follows:1. the metal keeps its name and is named and written first.– for transition metals, we use roman numerals to denote its charge.2. the nonmetal keeps its base name but has its ending changed to –ide.for cobaltic iodidecobaltic  → transition metal → +2 charge → co2+iodide → group 7a → -1 charge → i-criss-cross the charges and make them the subscript of the other ioncobaltic iodide → coi2answer: cobaltic iodide is an ionic compound with a formula of coi2 i. given:valency of carbon is 4valency of chlorine is 1by applying criss-cross method:formula: ccl4thus, the formula for carbon tetrachloride is ccl4.ii. given:valency of element x is 1valency of oxygen is 2by applying criss-cross method:formula: x2o