Reading Assignment 8.1 - 8.3
True or false: In order to balance the reaction of hydrogen gas (H2) with oxygen gas (O2) to form liquid H2O, a student adds a subscript of 2 to H2O (forming H2O2). This is an acceptable method of balancing the reaction described. True False
False
Which of the elements listed below appear as polyatomic molecules in their standard states? Select all that apply. Beryllium Fluorine Oxygen Neon Hydrogen
Fluorine Oxygen Hydrogen
Of the elements listed, select all that typically occur as diatomic molecules. Iodine Carbon Helium Nitrogen Sulfur
Iodine Nitrogen
"Aqueous solutions of calcium hydroxide and sodium phosphate react to form aqueous sodium hydroxide and solid calcium phosphate." In the reaction represented by the statement above, what are the reactants? Na3PO4 Ca3(PO4)2 Ca(OH)2 NaOH H2O
Na3PO4 Ca(OH)2
In a balanced chemical equation, which of the following must be the same on both sides of the equation? Number of molecules Potential energy Number of atoms of each element Phase labels
Number of atoms of each element
Correctly order the steps used in a combustion analysis experiment to determine the empirical formula of an organic compound.
1.) The mass of orginal sample is determined by weighing 2.) The sample is heated in the presence of oxygen. 3.) The CO2 and H2O produced by the combustion are trapped separetly 4.) The mass of each product is determined, From the masses of CO2 and H2O collected, the percent composition and empirical formula are calculated.
What is the empirical formula of a compound containing C, H, and O if combustion of a 0.500-g sample of the compound produces 0.955 g CO2 and 0.587 g of H2O? (Put a number in every blank, even if it is a 0 or 1.)
Blank 1: 2 Blank 2: 6 Blank 3: 1
A chemical equation is a statement using chemical that expresses both the identities and the relative of the reactants and products involved in a chemical or physical change.
Blank 1: formulas, symbols, formula, symbol, formulae, or notation Blank 2: quantity, quantities, amounts, amount, proportions, ratios, moles, molar ratios, molar ratio, or ratio
Hydrocarbons are compounds that contain only carbon and hydrogen. Combustion of a sample of a particular hydrocarbon gave 5.86 g of CO2 and 1.37 g of H2O. What is the empirical formula of the hydrocarbon? C2H7 C4H C7H8 C7H4 CH
C7H8
Given the balanced equation below, determine the moles of HCl required and the mass of AgCl formed from the complete reaction of 18.3 g of Ag2S. Ag2S (s) + 2HCl (aq) → 2AgCl (s) + H2S (g) 0.148 mol HCl 21.2 g of AgCl 10.6 g of AgCl 7.38 × 10-2 mol HCl
0.148 mol HCl 21.2 g of AgCl
Correctly order the steps necessary to determine the empirical formula of a compound from combustion analysis data.
1.) Determine the masses of C and H from the masses of CO2 and H2O 2.) Determine the mass of O, if present, by subtracting the masses of C and H from the total mass of the initial sample. 3.) Determine the number of moles of each element in the compound, and use the results as subscripts in a chemical formula 4.) Convert the subscripts in the formula to whole numbers, by dividing each by the smalleste subscript.
Correctly order the steps necessary to solve for the mass of a product, or second reactant required, given the mass of one of the reactants in a chemical process. Start with the first step at the top of the list.
1.) Write a balanced equation for the reaction. 2.) Covert the given mass into moles using molar mass. Convert moles of A to moles of B using a conversion factor derived from the balanced equation. 3.) Convert the moles of the second substance to mass using its molar mass.
Correctly order the steps necessary to balance a chemical equation.
1.) Write an unbalanced equation 2.) Balance the atoms of each element in turn, by adding the coeffcients before the chemical formulas of reactants and products--compounds first, elements last. 3.) Adjust the coefficients duch that the smallest whole-number coefficients are used. 4.) Do a final check to make sure the equation is balanced.
2S (s) + 3O2 (g) → 2SO3 (g) Which of the following gives the correct setup for calculating the number of moles of SO3 that will form from the complete reaction of 1.5 mol of O2, according to the balanced reaction equation above? 1.5 × 3 × 2 1.5×2/3 1.5/2x3 1.5×3/2
1.5x2/3
3H2 (g) + N2 (g) → 2NH3 (g) Calculate the mass of NH3 produced by the complete reaction of 2.55 g of H2 with excess N2 according to the equation above. 1.70 g 1.69 g 21.5 g 14.4 g
14.4 g
Select all the conversion factors that correctly represent the molar relationships in this balanced equation 2Al + 3Cl2 → 2AlCl3. 2 mol Al/3 mol Cl2 2 mol AlCl3 / 2 mol Al 1 mol Al / 2 mol AlCl3 2g Al / 3g Cl2
2 mol Al/3 mol Cl2 2 mol AlCl3 / 2 mol Al
Balance the unbalanced equation below, using lowest possible whole-number coefficients, then match each substance to the correct coefficient as indicated. Al2S3 (s) + H2O (l) → Al(OH)3 (aq) + H2S (g) Al2S3 H2O Al(OH)3 H2S
Al2S3 = 1 H2O = 6 Al(OH)3 = 2 H2S = 3
Which of the following statements are correct interpretations of the balanced equation 4C (s) + S8 (s) → 4CS2 (l)? Select all that apply. Carbon and S8 are reactants and CS2 is the product. 4 moles of carbon react with 1 mole of S8 to form 4 moles of CS2. 4 grams of carbon react with 1 gram of S8 to form 4 grams of CS2. 4 atoms of carbon react with 1 molecule of S8 to form 4 molecules of CS2.
Carbon and S8 are reactants and CS2 is the product. 4 moles of carbon react with 1 mole of S8 to form 4 moles of CS2. 4 atoms of carbon react with 1 molecule of S8 to form 4 molecules of CS2.
Match each reaction type with its distinguishing feature.
Combination - Two or more reactants combine to form a single product. Decomposition - A single reactant forms two or more products. Combustion - A reactant rapidly reacts with O2(g) to form oxides, such as CO2(g).
Which of the following actions are permitted in balancing a chemical equation? Inserting a coefficient between two elements in the formula of a compound Inserting coefficients before the formulas of reactants and products Altering the formulas of reactants or products Multiplying all coefficients by a common factor Adding reactants or products
Inserting coefficients before the formulas of reactants and products Multiplying all coefficients by a common factor
Which of the elements listed below appear as polyatomic molecules in their standard states? Select all that apply. Nitrogen Argon Magnesium Phosphorus
Nitrogen Phosphorus
What information can be obtained from a combustion analysis? Select all that apply. Percent composition of an organic compound Empirical formula of an organic compound Molecular formula of an organic compound Molecular mass of an organic compound
Percent composition of an organic compound Empirical formula of an organic compound
Which of the following statements describe the information that can be gained from a balanced chemical equation? Select all that apply. The identities of substances involved. The physical states of reactants and products, usually. The relative quantities (moles) of the substances involved. How fast a given reaction proceeds. The temperature at which a reaction is carried out.
The identities of substances involved. The physical states of reactants and products, usually. The relative quantities (moles) of the substances involved.
Select all the statements that correctly describe the symbols used to write a balanced equation. The symbol (g) indicates a substance in the gas phase. The symbol (s) is used for a powdered substance. The transformation of reactants into products is represented with an equal sign, =. The symbol (s) indicates that a substances is in solution. Reactants or products that are dissolved in water are given the symbol (l).
The symbol (g) indicates a substance in the gas phase. The symbol (s) is used for a powdered substance.
Which of the following statements correctly interpret the balanced chemical equation 4HCl (aq) + MnO2 (s) → MnCl2 (aq) + 2H2O (l) + Cl2 (g)? Select all that apply. Water is both a solvent and a product in this reaction. 4.00 g of HCl reacts with 1.00 g of MnO2. The MnO2 used in this reaction is a solution. The MnCl2 produced is dissolved in water. HCl is a reactant in this equation.
Water is both a solvent and a product in this reaction. The MnCl2 produced is dissolved in water. HCl is a reactant in this equation.
When the following chemical equation is balanced correctly, what is the correct coefficient for each species? (Enter ALL numbers, including the digit 1, if required.) SO2(g) + O2 (g) → SO3 (g) blank 1 SO2 blank 2 O2 blank 3 SO3
blank 1 = 2 or two blank 2 = 1 or one blank 3 = 2 or two
N2O4 → 2NO2 In the reaction represented by the chemical equation above, NO2 is the formula of the ______ and N2O4 is the formula of the ______. product, reactant reactant, product
product, reactant
Match each symbol used in writing a chemical equation with its correct meaning. → (s) (aq) Δ (l)
→ - indicates the conversion of reactants to products (s) - indicates a substance in the solid state (aq) - indicates a substance dissolved in H2O Δ - Indicates that the reaction is heated (l) - indicates a substance in the liquid state
Which of the following steps would be required to convert between the masses of two substances that are related through a chemical reaction? (For example, calculating the mass of product formed from the mass of a reactant.) Select all that apply. Convert from the given mass to moles of the same substance. Write a balanced chemical equation for the reaction. Use the coefficients from the balanced equation to convert directly from the mass of one substance to the other. Calculate the molar masses of all substances in the reaction. Write a conversion factor using the coefficients from the balanced equation, and convert to moles of the second substance.
Convert from the given mass to moles of the same substance. Write a balanced chemical equation for the reaction. Write a conversion factor using the coefficients from the balanced equation, and convert to moles of the second substance.
Correctly place the steps in order for determining the molecular formula of a compound from combustion analysis data, if the approximate molar mass is known.
1.) Determine the empirical formula of the compound from the combustion analysis data. 2.) Use the empirical formula to calculate the empirical molar mass. 3.) Divide the approximate molar mass of the compound by the empirical molar mass, and round the quotient to the nearest integer. 4.) Multiply each subscript in the empirical formula by the integer obtained.
In a(n) reaction, a single product is formed from two or more reactants. The opposite of this reaction type is a(n) reaction, in which a single reactant produces two or more products.
Blank 1: combination Blank 2: decomposition
Which statement does NOT correctly describe a step in determining the empirical formula of a compound from combustion analysis data? Compare the relative number of moles of each element to determine the empirical formula. Determine the masses of C and H in the sample from the masses of CO2 and H2O produced in the combustion. Determine the mass of a third element, if present, from the mass of its oxide produced in the combustion. Determine the number of moles of each element in the sample.
Determine the mass of a third element, if present, from the mass of its oxide produced in the combustion.
A student has done experiments to determine the empirical formula and the approximate molar mass of a substance. Which of the following methods should be used to determine the molecular formula? Divide the original mass of the sample by the empirical formula mass. Add up the empirical formula mass and multiply it by the approximate molar mass. Divide the approximate molar mass by the empirical formula mass.
Divide the approximate molar mass by the empirical formula mass.
Which of the substances below are represented with their proper formulas? Elemental sodium, Na+ Elemental oxygen, O2 Elemental copper, Cu Elemental phosphorus, P4 Elemental boron, B2
Elemental oxygen, O2 Elemental copper, Cu Elemental phosphorus, P4
