The chemical equation provides a variety of quantitative information for the calculations of combining weights of materials involved in a chemical process. The coefficients of a balanced equation tell us the relative formula units of reactants and products participating in a reaction. For instance: C_8 H_18+12½O_2→8〖CO〗_2+9H_2 O … (3.7) Note: (i) A balanced equation remains valid if each of the coefficients in Eq. (3.7) is multiplied by the same number. (ii) The basis selected for calculations is mass rather than moles. (a) If mass is given, the given mass is converted to moles using molecular weight. (b) Then using appropriate stoichiometric ratio, obtain required moles of products and reactants. (c) Change moles of …show more content…
Calculate the following items: (a) The percentage of excess carbon furnished, based on the principal reaction. (b) The percentage conversion of Fe2O3 to Fe. (c) The pounds of carbon used up and the pounds of CO produced per ton of Fe2O3 charged. (d) What is the selectivity in this process (of Fe with respect to FeO)? Solution Setting up the mole equivalent for the principal reaction as follows; Fe_2 O_3 + 3C → 2Fe + 3CO Initial mass: 1 100 lb 300 lb - - Mass at time, t: - - 600 lb Molar mass: 160 12 56 Number of moles: 6.875 25.00 10.714 Mole equivalent: 6.875 8.333 5.357 In addition, setting up the mole equivalent for the undesired side reaction as follows; Fe_2 O_3 + C → 2FeO + CO Initial mass: 1 100 lb 300 lb - - Mass at time, t: - - 91.5 lb Molar mass: 160 12 72 Number of moles: 6.875 25.00 …show more content…
91.5 lb/72 (molar mass of FeO)) ∴Selectivity of Fe=(10.714 moles Fe)/(1.271 moles FeO)=8.43 (mole Fe)⁄(mole FeO) Example 3.6: Chemical Equation and Stoichiometry Question A common method used in manufacturing sodium hypochlorite bleach is by the reaction: Cl_2+2NaOH→NaCl+NaOCl+H_2 O Chlorine gas is bubbled through an aqueous solution of sodium hydroxide, after which the desired product is separated from the sodium chloride (a by-product of the reaction). An aqueous solution of NaOH containing 520.45 kg of pure NaOH is reacted with 386.82 kg of gaseous chlorine to give 280.91 kg of NaOCl. (a) What was the limiting reactant? (b) What was the percentage excess of the excess reactant used? (c) What is the degree of completion of the reaction, expressed as the moles of NaOCl formed to the moles NaOCl that would have formed if the reaction had gone to completion? (d) What is the yield of NaOCl per amount of chlorine used (on a weight basis)? Solution First, setting up the mole equivalent as follows: Cl_2 + 2NaOH→NaCl+NaOCl+H_2 O Initial mass (kg): 386.82 520.45 - -
Question3: Experiment 3 The unknown acid sample was 1 • Monoprotic Acid Trails Initial NaOH solution (mL) final NaOH solution (mL) The volume of NaOH to titrate the acid (mL) Amount of Unknown Acid sample 1 (g) The moles of the Unknown Acid (mol) Molar mass of the Unknown Acid (g/mol) A 3.38 28.31 24.93 0.150 0.0026 57.69 B 0.18 29.32 29.14 0.175 0.0029
The molar heat of combustion of a compound is 1250 kJ/mole. If 0.115 moles of this compound in a bomb calorimeter with 2.50 L of water, what would the temperature increase be? If change in heat is positive it is an _______ reaction If change in heat is negative it is an_______ reaction
In order to find the amount of a product made during a double displacement reaction, the product has to be separated from the solution. From this number of moles of precipitate can be calculated. From there the number of moles of reactants can be calculated using the mole ratios of the particular reaction that occurred. As seen in Table 5 it is shown that by finding out the number of moles of the unknown, the molar mass of the unknown can be calculated. From the found mass of the unknown compound, the mound of the original ion can be found.
Because of this, three different products (as previously mentioned) are potentially formed.1 The compound created from the reaction can be analyzed to determine
Exercise 1 1. Suppose a household product label says it contains sodium hydrogen carbonate (sodium bicarbonate). Using your results from Data Table 1 as a guide, how would you test this material for the presence of sodium bicarbonate? B BoldI ItalicsU Underline Bulleted list Numbered list Superscript Subscript33 Words
3H2O. This chemical would be called calcium sulfate trihydrate. When finding the mass of this chemical, you find the mass of the calcium sulfate and then add 3 times the mass of water to it. (40.08 + 32.066 + 4(15.999) + 3(2(1.0079) + 15.999)) = 190.19 g/mol.
Stoichiometry is a method used in chemistry that involves using relationships between reactants and products in a chemical reaction, to determine a desired quantitative data. The purpose of the lab was to devise a method to determine the percent composition of NaHCO3 in an unknown mixture of compounds NaHCO3 and Na2CO. Heating the mixture of these two compounds will cause a decomposition reaction. Solid NaHCO3 chemically decomposes into gaseous carbon dioxide and water, via the following reaction: 2NaHCO3(s) Na2CO3(s) + H2O(g) + CO2(g). The decomposition reaction was performed in a crucible and heated with a Bunsen burner.
The other time where mass could have been lost was during reaction 3, more specifically each time the liquid was decanted. Although a few black sand-coffee grains of the copper (II) oxide lost do not seem like a significant amount, they do have an impact on the final result, and each time a few of the grains were accidentally decanted could have an impact on why our final recovered mass was less than the initial amount that we began
As the unknown acid was titrated, one of the products formed in the reaction was the ion of the unknown acid, or the conjugate base which, according to the Brønsted-Lowry theory, was formed as a result of the acceptance of a hydrogen ion from NaOH. When the moles of the unknown acid and the
Verna Wang Hannah Palmer CHEM 101-069 Lab 11-19-16 Stoichiometry and Limiting Reagents Lab Report Purpose: We are using the reaction of sodium hydroxide and calcium chloride to illustrate stoichiometry by demonstrating proportions needed to cause a reaction to take place. Background: Just like a recipe would call for a specific amount of one ingredient to a specific amount of another, stoichiometry is the same exact method for calculating moles in a chemical reaction. Sometimes, we may not have enough of or too much of one ingredient , which would be defined as limiting and excess reagent, respectively.
CONCLUSION When you put an egg in vinegar, we see that the shell dissolves, but do you ever wonder why? An egg is made mostly out of calcium carbonate which reacts with an ingredient in vinegar, acetic acid. Acetic acid is about 4% of the vinegar and what breaks apart the solid calcium carbonate crystals. The bubbles we see, from the egg, is the carbonate that make carbon dioxide and the other calcium ions float free. This is the equation: CaCO3 (s) + 2 HC2H3O2 (aq)
Procedure A. Preparation of NaOH solution The molarity of a solution is the ratio of the number of solutes dissolved in a liter of solution. To figure out the needed mass (in grams) of NaOH pellets to be dissolved in a 0.25 L of water, remember that a mole is equivalent to the quotient of mass over the molar mass of the substance. This was used to rearrange the base formula and to derive the mathematical equation of mass in terms of molarity. mass (g) =
AIM To design an investigation to study the kinetics of a reaction of your choice RESEARCH QUESTION With respect to hydrochloric acid (HCl), what is the order of reaction in the reaction between HCl and calcium carbonate (CaCO3) determined by changing the concentration of HCl and measuring the volume of carbon dioxide gas (CO2) collected in 30 seconds whilst keeping the mass of the powdered CaCO3 constant and the temperature of the reaction system at 25oC? BACKGROUND INFORMATION Calcium carbonate (CaCO3) is a chemical compound that is commonly found in rocks such as chalk, limestone, marble and travertine in all parts of the world. It also used as a form of medicine as a dietary supplement for a person with insufficient calcium intake because calcium is needed by the body for healthy bones, muscles, nervous system, and heart. CaCO3 is also used as an antacid to relieve
℃^(-1)×6.40℃±3.1 %=1337.6 J±4.06 % ∆H=(-1337.6 J±4.06 %) /(0.025 mol ±0.16 %)= -53504 J m〖ol〗^(-1)±4.22 % ∆H=-53504 J m〖ol〗^(-1)±4.22 %÷1000=-54 kJ m〖ol〗^(-1)±4.22 % Conclusion and
Explain how the molarity of the standard solution (the alkali) was calculated in the experiment (equation explained)- 0.1M of NaOH is required, this equation will be used: Concentration = moles volume This will be rearranged to find the moles needed to carry out the experiment. The concentration of the experiment using NaOH is 0.1M so we just need to rearrange the equation to find the molarity. 0.1 x 0.250 = 0.0250 moles Number of moles =