In 1961, scientists agreed that the atomic mass unit (amu)would be defined as the mass of an atom of 12C. Before then,it was defined as the average mass of an atom of naturally occurring oxygen (a mixture of 16O, 17O, and 18O). The current atomic mass of oxygen is 15.9994 amu. (a) Did Avogadro’snumber change after the definition of an amu changed and, if so,in what direction? (b) Did the definition of the mole change?(c) Did the mass of a mole of a substance change? (d) Before1961, was Avogadro’s number 6.021023(when considered tothree significant figures), as it is today?

Q: mixture of O2 (g) and H2 (g) explosively react to form steam H2O (g) in the presence of an electric…

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Q: Write the balanced chemical equation for the reaction of these pairs of reactants: (a) Calcium and…

A: a) Ca + Br2 = CaBr2 . b) 4Al + 3O2 = 2Al2O3

Q: The solid fuel booster rockets of the space shuttle are based on the following reaction between…

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Q: A student heated a 3.32-g sample of a hydrate and recovered 2.02 g of an anhydrous compound. (b)…

A: Given : Mass of anhydrous MgC2O4 recovered = 2.02 g

Q: Grignard reagents, which contain a C—Mg bond, have thegeneral formula CH₃—(CH₂)ₓ—MgBr and are…

A: GIVEN: General formula CH₃—(CH₂)ₓ—MgBr To Solve: a)mass percentof Mg if x=0 b) mass percent of Mg if…

Q: (a) Calculate the molar mass of ammonium nitrate, NH4NO3. (b) What is the mass percent of nitrogen…

A: (a) Molar mass of a molecule = sum of atomic masses of all the constituent elements      Molar mass…

Q: Calculate (to the nearest 0.1 u) the formula mass of these compounds. (a) boron trifluoride, BF3…

A: The compounds given are BF3, SrSO4 and CCl4.

Q: Write a balanced chemical equation for the photosynthesis reaction in which gaseous carbon dioxide…

A: The process by which the plants make their own food with the aid of sunlight is termed as…

Q: (a) A compound MX2 is formed from the M²+ and X ions. The compound contains 86.8% of X by mass. In a…

A: a) Given that,molecular formula of the given =  MX2 The percentage of X in the compound= 86.8% In a…

Q: In the following diagram, the white spheres represent hydrogenatoms and the blue spheres represent…

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Q: Even though lead is toxic, lead compounds were used in ancient times as white pigments in cosmetics.…

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Q: 7. Elemental phosphorus is produced by the reaction, 2 Ca3(PO4)2 + 6 SiO₂ + 10 C →6 CaSiO3 + 10 CO +…

A: The moles of Ca3(PO4)2 is 6.00 mol.The moles of SiO2 are 20.0 mol.The moles of C is 24.0 mol.To…

Q: A binary compound of oxygen and an unknown element, x, has the formu XO and is 39.70 mass % oxygen.…

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Q: Aqueous solutions of ammonia (NH3) and bleach (activeingredient NaOCl) are sold as cleaning fluids,…

A: Hey, since there are multiple sub-part questions posted, we will answer first three questions. If…

Q: Write a balanced chemical equation based on the following description: the reaction of gaseous C₅H₄…

A: The reactants given are  1) gaseous C5H4 i.e C5H4 (g) 2) Oxygen gas i.e O2 (g) And the products…

Q: A sample of NaCr(SO₂)₂.10H₂O was heated in a crucible, yielding 1.27 g of the corresponding…

A: The molar mass of NaCr(SO4)2 is = 267 g/mol The molar mass of H2O is = 18.0 g The mass of NaCr(SO4)2…

Q: (a) What is the chemical formula of eugenol, the main contri butor to the aroma of cloves? (b)…

A: a) We have to find chemical formula of eugenol, the main contributor to the aroma of cloves.…

Q: When active metals such as sodium are exposed to air, they quickly form a coating of metal oxide.…

A: Please find the below attachments.     Thank you

Q: In an experiment designed to produce calcium oxide by the chemical reaction: 2Ca + O2 → 2CaO…

A: Given reaction is,  2Ca + O2 → 2CaO Also Given is, 104.5 g of CaO was obtained out of a possible…

Q: Uranium is used as a fuel, primarily in the form of uranium(IV) oxide, in nuclear power plants. A…

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Q: Calculate (to the nearest 0.1 u) the formula mass of these compounds. (a) carbon monoxide, CO  u…

A: Formula mass is the mass which is obtained from the formula of any compound. Recall the atomic…

Q: Uranium is used as a fuel, primarily in the form of uranium(IV) oxide, in nuclear power plants. A…

A: To solve this problem first we have to calculate the mass of oxygen combined , then we will…

Q: (a) How many moles of ammonium ions are in 0.642 g of ammonium carbonate? 8.04e21 X mol (b) What is…

A: We have to calculate the required quantities.

Q: Hydrogen cyanide, HCN, is prepared from ammonia, air, and natural gas (CH4) by the following…

A: Limiting reactant :-  A reactant which is present in lesser number of moles than required as per…

Q: A possible practical way to eliminate oxides of nitrogen (such as NO2) from automobile exhaust gases…

A: C3N3(OH)3→3HCNOUnbalanced equation,C3N3(OH)3+NO2→N2+CO2+H2O

Q: Sodium reacts with chlorine to form sodium chloride. In an experiment a student reacted 1.50 g of…

A: A balanced chemical reaction is a reaction that contains the same number of atoms on the reactant…

Q: 7. Elemental phosphorus is produced by the reaction, 2 Ca3(PO4)2 + 6 SiO₂ + 10 C6 CaSiO3 + 10 CO +…

A: The given reaction is 2Ca3(PO4)2 +6SiO2 +10C→ 6 CaSiO3 +10 CO+P4 moles of Ca3(PO4)2 = 9.00 moles…

Q: During the 1950s, pentaborane-9 was tested as a potential rocket fuel. However, the idea was…

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Q: The percent composition of an unknown substance is 46.43% C, 25.77% O, 18.05% N, and 9.74% H. What…

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Q: Calamine is a naturally occurring zinc silicate that contains the equivalent of 67.5% zinc oxide,…

A: Using mole concept we can easily determine how much reactants  is used or composition of elements in…

Q: nediamine (CH16N2) is one of the starting materials for the p red from adipic acid (CGH1004) by the…

A: Molar mass of adipic acid = 146 g Molar mass of C6H16N2 = 116 g Form balanced reaction,  146 g…

Q: 3.) Tetraphosphorus decaoxide reacts with water to form phosphoric acid, a major industrial acid. In…

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Q: Balance these chemical equations. (Use the lowest possible whole number coefficients.) (a)    SO2 +…

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Q: A sample of calcium nitrate crystal hydrate with its mass of 1.1808 g was heated at 150oC resulting…

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Q: Calculate (to the nearest 0.1 u) the formula mass of these compounds. (a) acetaminophen, C8H9NO2…

A: Formula mass is the sum of all the atomic masses present in that compound. Atomic masses: C = 12 u N…

Q: How many atoms are there in 75 molecules of acetic acid, CH3CO2H? A compound contains, by mass,…

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Q: When potassium chlorate is subjected to high temperatures, it decomposes into potassium chloride and…

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Q: MgSO, zH2O, is heated to 250 °C, all the water of hydration is lost. OH Heatinga MgSO, remains. How…

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Q: If 73% of the SO₂ could be removed by reaction with powdered calcium oxide CaO, via the reaction…

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Q: Calculate the molar mass of each of the following:(a) the anesthetic halothane, C2HBrClF3(b) the…

A: molar mass of a substance is the mass of the substance in1 mole .

Q: What is the total number of oxygen atoms on the right-hand side of this chemical equation? 2 Caz…

A: Given :- 2Ca2(PO4)2(s) + 4SiO2(s) + 12C(s) → 4CaSiO3(s) + P4(s) + 12CO(g)  To determine :- total…

Q: Fe3Br8 – an important source of potassium bromide is produced through the following two-stage…

A: The two-stage reaction for the formation of Fe3Br8 is: Stage 1: 3 Fe + 3 Br2 → 3 FeBr2  Stage 2: 3…

Q: Fe3Br8 – an important source of potassium bromide is produced through the following two-stage…

A: Given following balanced Chemical equations -  Stage 1: 3 Fe + 3 Br2 ----> 3 FeBr2 Stage 2: 3…

Mole Concept

Mole concept is a method to determine the amount of any substance that consists of some elemental particles using a grouping unit called ‘mole’. The mole concept enables one to handle the large amount of small elementary particles. The mole concept can be used in many calculations related to mole calculation, molar amount, mole ratio, and so on, which are significant in chemistry.