true or false(a) if a substance is oxidised, it is gaining electrons.(b) if an ion is oxidised, its oxidation number increases.

One of the ways to remove nitrogen monoxide gas, a serious source of air pollution, from smokestack emissions is by reaction with ammonia gas, NH3. The products of the reaction, N2 and H2O, are not toxic. Write the balanced equation for this reaction. Assign an oxidation number to each element in the reactants and products, and indicate which element is oxidized and which is reduced.

4-21 The brilliant white light in some firework displays is produced by burning magnesium in air. The magne sium reacts with oxygen in the air to form magnesium oxide. Write a balanced equation for this reaction.

When solutions containing mercury(II) nitrate and potassium iodide were mixed, a red-orange precipitate resulted. (a) What type of reaction occurred? (b) Write the chemical equation. (c) What is the name and formula for the solid product?

'(d) sodium cnionae is an ionic compound. ltcontains sodium ions, Na+ and chloride ions, CI-When molten sodium chloride is electrolysed, sodium metal and chlorine gas are formed. Describe how the sodium ions and chloride ions in solid sodium chloride are converted into sodium and chlorine by electrolysis.

Answer true or false.  (a) A net ionic equation shows only those ions that undergo chemical reaction.  (b) In a net ionic equation, the number of moles of starting material must equal the number of moles of product.  (c) A net ionic equation must be balanced by both mass and charge.  (d) As a generalization, all lithium, sodium, and potassium salts are soluble in water.  (e) As a generalization, all nitrate (NO3 –) salts are soluble in water.  (f) As a generalization, most carbonate (CO3 2–) salts are insoluble in water.  (g) Sodium carbonate, Na2CO3, is insoluble in water.  (h) Ammonium carbonate, (NH4)2CO3, is insoluble in water.  (i) Calcium carbonate, CaCO3, is insoluble in water.  (j) Sodium dihydrogen phosphate, NaH2PO4, is insoluble in water.  (k) Sodium hydroxide, NaOH, is soluble in water.  (l) Barium hydroxide, Ba(OH)2, is soluble in water.

Most abundant metal on the surface of the earth:(a) Iron(b) Aluminium(c) Calcium(d) Sodium

A key step in balancing chemical equations is correctly identifyingthe formulas of the reactants and products. For example,consider the reaction between calcium oxide, CaO(s),and H2O(l) to form aqueous calcium hydroxide. (a) Write abalanced chemical equation for this combination reaction,having correctly identified the product as Ca(OH)2(aq).(b) Is it possible to balance the equation if you incorrectly identifythe product as CaOH(aq), and if so, what is the equation?

Which one(s) of the following reactions is(are) redox reactions? (a) Na (s) + H2O (l) → NaOH (aq) + H2 (g) (b) NaOH (aq) + HCl (aq) → NaCl (aq) + H2O (l) (c) H2O (l) → O2 (g) + H2 (g) (d) Ag+ (aq) + Cl- (aq) → AgCl (s)

When each of the following pairs of aqueous solutions is mixed, does a precipitation reaction occur? If so, write the formula and name of the precipitate. (Type your answer using the format CO2 for CO2. Type NONE in the blanks if there is no precipitation reaction.) (a) lead(II) nitrate + potassium bromideformulaname(b) sodium sulfide + nickel(II) sulfateformulaname