CHM110H5 Study Guide - Final Guide: Molar Mass

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harlequinhound715

9 Feb 2016

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1: the following two reactions are observed in the experiment; the h2o and d20 react completely with excess chlorine to create hcl, dcl and o2. The number of moles of the reactants are unknown, so x=the moles of h2o and y=the moles of d20. The same products are then reacted with excess chlorine to produce the second equation: xh2o(aq)+ yd20(aq) +cl2(g) 2xhcl(aq)+2ydcl(aq)+o2(aq) 2xhcl(aq) + 2ydcl(aq) + agno3(aq) agcl(s) +hno3(aq) + dno3(aq) The following two equations can be expressed: the 1st equation represents the mass of h2o plus the mass of d2o is equal to 1. 00g. The 2nd equation represents the moles of agcl equal to the sum of the moles of h20 and d20: (1) 18x + 20y = 1. 00g; (2) 2x + 2y = nagcl. The moles of agcl can be calculated, as you are given the mass: nagcl= 0. 38g/143. 4gmol-1 =2. 6499x10-3 mol.

Related Questions

3. Write the product formed in the following reactions in the space provided. If the reaction does not take place write NO RXN. Indicate physical states by (s), (l), (g), (aq). Make sure the reaction is balanced! Please write the net ionic equation below.

a. Pb(CH₃CO₂)_2(aq) + Na₂SO₄_(aq) Ã

b. AgNO_3(aq) + NH₄Br_(aq) Ã

4. Balance the following reactions and answer the questions below.

a. Al_(s) + HCl _(aq) Ã AlCl₃ + H₂

What is the element that is oxidized _______________________

What is the element that is reduced _______________________

Which compound is the oxidizing agent ____________________

Which compound is the reducing agent ____________________

b. Na_(s) + FeCl₂ Ã NaCl + Fe

What is the element that is oxidized _______________________

What is the element that is reduced _______________________

Which compound is the oxidizing agent ____________________

Which compound is the reducing agent ____________________

8. Using the unbalanced equation how many grams of lithium nitrate will be needed to make 250g of lithium sulfate, assuming that you have an adequate amount of lead (IV) sulfate to do the reaction.

Pb(SO₄)_2(aq) + LiNO_3(aq) Ã Pb(NO₃)_4(s) + Li₂SO_4(aq)

9. Using the following equation determine how many grams of sodium fluoride can react with 184.4 grams of magnesium.

Mg + NaF₂ Ã MgF₂ + Na

10. Determine how many Oxygen atoms are present in 46.7g of Zr(SO₄)₂

10. Given the following unbalanced equation:

Al₂O_3(aq) + Fe_(s) Ã Fe₂O_3(aq) + Al_(s)

Determine how many grams of Iron (III) Oxide can be formed if 224 grams of aluminum oxide is reacted with iron.

Multiple choice:

10b. Which of the following statement is true about 1 mole of Ca(NO₃)₂?

a. It contains the 6.02 x 10²³ NO₃^- ions.

b. It weighs 146 grams

c. It will most likely dissolve in a bucket of water.

d. It will produce equal number of Ca⁺² and NO₃^- ion in a solution.

10. How many molecules are present in 48.0 grams of oxygen gas? (O₂)

a. 6.02 x10²³ b. 1.81 x10²⁴ c. 9.03 x10²³ d. 1.03x10²⁴

12. If there are 12 moles of carbon in 1 mole of sucrose, C₁₂H₂₂O_11.How many atoms of carbon are there in 1 mole of sucrose?

a. 1 x6.03 x 10²³ b. 12x 6.03 x 10²³ c. 22 x 6.03 x 10²³

13. Determine the oxidation state of oxygen in the compound Cr₂O₃ in the following equation:

Cr₂O_3(s) + 2Al_(s) Ã Cr_(s) + Al₂O_3(s)

-2 b. -6 c. 6 d. 2

16. Determine the oxidation state of Al in the following equation:

Al_(s) + HCl Ã AlCl_3(aq) + H₂

+2 b. 0 c. +3 d. -5

I need help with questions 2-4 I can't figure them out.

Introduction An important type of reaction mechanism is the transfer of electrons from one species to another effecting a change in oxidation state. This gain or loss of electrons is referred to as reduction and oxidation, respectively. For example, consider the two balanced, chemical equations (1 & 2) that follow Cu (s) D Cu (aq) 2e (1) Cl2(aq) 2e D 2Cl (aq) (2) The first equation (1) shows elemental copper metal with a oxidation state of zero forming aqueous copper(Il) ions having an oxidation state of +2. This gain in oxidation number, 0 to +2, is called oxidation. The second equation (2) show elemental chlorine having an oxidation state of zero forming chloride ions in aqueous solution with an oxidation state of This decrease in oxidation number, 0 to -1, is called reduction. In any chemical reaction, the electrons gained or lost are conserved, i.e.. there is no net gain or loss of electrons. In fact, the two reactions illustrated above could occur simultaneously with the electrons lost by copper, gained by the chlorine in aqueous solution. Since the copper provides the electrons that subsequently reduce the chlorine copper is referred to as the reducing agent. Likewise, since the chlorine is accepting the electrons from copper, which subsequently oxidizes the copper, chlorine is referred to as he oxidizing agent. The two reactions above (1 & 2) are called half-reactions, as much as they each constitute one-half of the total reaction Equation 1 is the oxidation half reaction showing Cu(s) losing two electrons. In Equation 2, Cla(aq) gains two electrons and is the reduction half-reaction. If these two half-reaction are added together the result is the total oxidation-reduction reaction or "redox" reaction. Adding the two equations yields (3). Cu(s) Cl2(aq) D Cu (aq) 2CI (aq) (3) Whether or not the above reaction is spontaneous proceeds from reactants to products without input of energy into the system, may be determined by observing the reaction mixture if the reactants and products differ greatly in their appearance. Copper metal is a bright copper color and chlorine in aqueous solution will appear yellow. The Cu ion may turn the liquid part of the mixture blue, however, the Cris colorless and cannot be observed directly. Copper, like many of the transition metals, exhibits a variety of oxidation states depending upon the chemical environment in which it is found. In a strong reducing environment copper may exist as the free metal, Cu(s). An example of such a situation is illustrated in the following chemical equation (4). 4Cuo(s) CH4(g) D 4Cu(s) CO2(g) 2H2O(l) (4)

CHM110H5 Study Guide - Final Guide: Molar Mass

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