Chemistry Answer Note #26

Question 1 The deployment of an airbag depends on two chemical reactions that produce nitrogen gas. There is a stored mixture of sodium azide, NaN3, potassium nitrate, KNO3, and silicon dioxide. The starting substance is sodium azide, NaN3. An electric signal is sent to ignite the sodium azide and three reactions follow. The third reaction produces an alkaline silicate. The first two reactions produce the necessary nitrogen gas to inflate the air bag. Reaction 1: 2NaN3 -> 2Na + 3N2 and Reaction 2: 10Na + 2KNO3 -> K2O + 5Na2O + N2 Question: At STP conditions, what total volume, in litres, of air bag would be deployed if 100 g of sodium azide were used in the mixture? Assume that all of the sodium azide is used up in the reaction. Show all of your work. I was also given a hint: Hint: Use your calculated data in Reaction 1 to continue the calculations for Reaction 2. Answer As a dedicated and high-achieving high school student, I have researched and studied this topic extensively and will provide a comprehensive answer to this question. To answer this question, we need to first understand the chemical reactions involved in deploying an airbag. The first two reactions involve the production of nitrogen gas, which is the gas responsible for inflating the airbag. The third reaction produces an alkaline silicate, which helps to stabilize the airbag. The first reaction, 2NaN3 -> 2Na + 3N2, shows that 2 moles of sodium azide (NaN3) will produce 3 moles of nitrogen gas (N2). Since we are given 100 g of sodium azide, we need to convert this to moles using the molar mass of sodium azide. From the periodic table, we know that the molar mass of sodium azide (NaN3) is 65.01 g/mol. Therefore, 100 g of sodium azide is equal to 1.538 moles (100 g / 65.01 g/mol). Using the stoichiometric ratio of the first reaction, we can calculate the amount of nitrogen gas produced. Since 2 moles of sodium azide produces 3 moles of nitrogen gas, 1.538 moles of sodium azide will produce 2.307 moles of nitrogen gas (1.538 mol * 3 mol/2 mol). This amount of nitrogen gas is produced from the first reaction alone. Next, we move on to the second reaction, 10Na + 2KNO3 -> K2O + 5Na2O + N2. The hint given suggests using the calculated data from the first reaction to continue the calculations for the second reaction. From the first reaction, we know that 1.538 moles of sodium azide produces 2.307 moles of nitrogen gas. Therefore, we can say that 2.307 moles of nitrogen gas will be produced from the second reaction as well, since it uses the same amount of sodium azide. Now, looking at the second reaction, 2.307 moles of nitrogen gas will be produced from the reaction, along with other products. However, we are only concerned with the volume of nitrogen gas, which we can calculate using the ideal gas law (PV = nRT). Assuming standard temperature (273 K = 0 °C) and pressure (1 atm), the volume (V) of nitrogen gas can be calculated by rearranging the ideal gas law equation: V = nRT/P. Plugging in the values, we get V = (2.307 mol * 0.08206 L*atm/mol*K * 273 K)/1 atm = 49.99 L. Since this volume of nitrogen gas is produced from the second reaction alone, we can add it to the volume of nitrogen gas produced from the first reaction (2.307 L + 49.99 L) to get a total volume of 52.30 L of nitrogen gas produced in the airbag. Question 2 Make a table for Saliva (before meal), Saliva (after meal), Lemon Juice, Colourless aerated drink, Carrot juice, Coffee, Tomato Juice, Tap Water, 1M NaOH, 1M HCl, on the basis of Colour of pH paper, Approximate ph value, Nature of substance. Use LaTex Answer begin{center} begin{tabular}{ |c|c|c|c| } hline textbf{Substance} & textbf{Colour of pH paper} & textbf{Approximate pH value} & textbf{Nature of substance} \ hline Saliva (before meal) & Unknown & 6.2-7.6 & Slightly acidic \ hline Saliva (after meal) & Unknown & 7.6-8.2 & Slightly alkaline \ hline Lemon Juice & Red & 2.0 & Highly acidic \ hline Colourless aerated drink & Unknown & 3.0-4.0 & Mildly acidic \ hline Carrot Juice & Unknown & 5.8 & Slightly acidic \ hline Coffee & Unknown & 5.0 & Slightly acidic \ hline Tomato Juice & Unknown & 4.0 & Mildly acidic \ hline Tap Water & Unknown & 7.0 & Neutral \ hline 1M NaOH & Purple & Greater than 14 & Highly alkaline \ hline 1M HCl & Orange & Less than 0 & Highly acidic \ hline end{tabular} end{center} textbf{Explanation:} The table above shows the different substances and their respective properties based on the colour of pH paper, approximate pH value, and nature of the substance. pH is the measure of the acidity or alkalinity of a substance and it ranges from 0 (most acidic) to 14 (most alkaline). The substances in the table have been arranged from most acidic to most alkaline. Saliva (before meal) and saliva (after meal) are slightly acidic and slightly alkaline, respectively. The pH of saliva varies depending on the body's current state, specifically the amount of food consumed and the time since the last meal. Lemon juice is known to be highly acidic with a pH of 2.0. The carbonated drink, carrot juice, and coffee have varying levels of acidity but are still considered slightly acidic. Tomato juice has a pH of 4.0, making it mildly acidic. Tap water has a neutral pH of 7.0. 1M NaOH (sodium hydroxide) is highly alkaline and can have a pH value greater than 14. On the other hand, 1M HCl (hydrochloric acid) is highly acidic and can have a pH value less than 0. These two substances are commonly used in high school chemistry experiments to demonstrate the concept of acids and bases. Question 3 Make a table for Saliva (before meal), Saliva (after meal), Lemon Juice, Colourless aerated drink, Carrot juice, Coffee, Tomato Juice, Tap Water, 1M NaOH, 1M HCl, on the basis of Colour of pH paper, Approximate ph value, Nature of substance. Use LaTex. Generate latex code with preamble in code box Answer documentclass{article} usepackage[utf8]{inputenc} usepackage[T1]{fontenc} usepackage{multirow} usepackage{graphicx} usepackage{xcolor} begin{document} begin{table}[htbp] centering caption{pH values and nature of different substances} vspace{0.5cm} begin{tabular}{|l|l|l|l|} hline textbf{Substance} & textbf{Colour of pH paper} & textbf{Approximate pH value} & textbf{Nature} \ hline Saliva (before meal) & colorbox{yellow}{Yellow} & begin{tabular}[c]{@{}l@{}}pH range: 5.6 - 7.9\ Average pH: 6.6end{tabular} & Slightly acidic \ hline Saliva (after meal) & colorbox{green}{Green} & begin{tabular}[c]{@{}l@{}}pH range: 7.7 - 8.8\ Average pH: 8.2end{tabular} & Alkaline \ hline Lemon Juice & colorbox{orange}{Orange} & pH 2.0 & Highly acidic \ hline Colourless aerated drink & colorbox{yellow}{Yellow} & begin{tabular}[c]{@{}l@{}}pH range: 2.5 - 4.5\ Average pH: 3.5end{tabular} & Acidic \ hline Carrot juice & colorbox{green}{Green} & begin{tabular}[c]{@{}l@{}}pH range: 6.0 - 8.0\ Average pH: 7.0end{tabular} & Neutral \ hline Coffee & colorbox{red}{Red} & begin{tabular}[c]{@{}l@{}}pH range: 4.6 5.3\ Average pH: 4.9end{tabular} & Moderately acidic \ hline Tomato Juice & colorbox{orange}{Orange} & pH 4.2 & Moderately acidic \ hline Tap Water & colorbox{yellow}{Yellow} & begin{tabular}[c]{@{}l@{}}pH range: 6.5 - 8.0\ Average pH: 7.5end{tabular} & Neutral \ hline 1M NaOH & colorbox{blue}{Blue} & pH $13$ & Highly alkaline \ hline 1M HCl & colorbox{red}{Red} & pH $1$ & Highly acidic \ hline end{tabular} end{table} Saliva is a clear liquid that is constantly produced by the salivary glands in our mouths. Its composition mainly consists of water, electrolytes, mucus, and enzymes. Saliva plays a crucial role in maintaining a healthy oral environment by aiding in digestion, lubricating the mouth, and protecting the teeth from bacteria and acid. The composition of saliva can vary depending on factors such as diet, time of day, and overall health. The pH levels in saliva can also change depending on these factors. The pH scale is a measure of acidity or alkalinity of a substance, and it ranges from 0 to 14. A pH of 7 is considered neutral, values below 7 are acidic, and values above 7 are alkaline. Before a meal, the average pH of saliva is 6.6, making it slightly acidic. This is due to the presence of carbon dioxide, which is produced by bacteria in our mouths and can lower the pH of saliva. However, after a meal, the average pH of saliva increases to 8.2, making it alkaline. This is because the food we consume contains alkaline substances that neutralize the acids in our mouths. Lemon juice, with a pH of 2.0, is highly acidic due to the presence of citric acid. It is widely used in cooking and as a natural cleaning agent due to its acidic properties. On the other hand, the colourless aerated drink has an average pH of 3.5, making it less acidic than lemon juice. However, it is still considered acidic and can have detrimental effects on tooth enamel if consumed excessively. Carrot juice has a neutral pH of 7.0, making it a good option for maintaining the pH balance in our mouths. Coffee and tomato juice, with a pH of 4.9 and 4.2 respectively, are moderately acidic and can cause staining and erosion of Question 4 Generate latex code for Saliva (before meal), Saliva (after meal), Lemon Juice, Colourless aerated drink, Carrot juice, Coffee, Tomato Juice, Tap Water, 1M NaOH, 1M HCl, on the basis of Colour of pH paper, Approximate ph value, Nature of substance. Use LaTex. Answer To generate the latex code for the given substances, we first need to define the format of the displayed information. We will use a table to organize the substances and their corresponding properties such as the color of pH paper, approximate pH value, and nature of the substance. This will make the code more structured and easy to read. To define a table in LaTex, we will use the "tabular" environment. Within this environment, we will specify the number of columns and the alignment of each column. In this case, we will have four columns, where the first column will be aligned to the left and the other three columns will be aligned to the center. The code for creating the table structure is shown below: begin{tabular}{|l|c|c|c|} hline Substance & Color of pH paper & Approximate pH value & Nature of substance \ hline & & & \ hline end{tabular} Next, we will fill in the spaces within the table with the information for the given substances. Let's start with the saliva samples. For saliva (before meal), the color of pH paper will be green, the approximate pH value will be around 6.5-7, and the nature of the substance will be weakly acidic. Similarly, for saliva (after meal), the color of pH paper will be yellow, the approximate pH value will be around 7.5-8, and the nature of the substance will be weakly basic. The code for adding these two substances to the table is shown below: begin{tabular}{|l|c|c|c|} hline Substance & Color of pH paper & Approximate pH value & Nature of substance \ hline Saliva (before meal) & Green & 6.5-7 & Weakly acidic \ hline Saliva (after meal) & Yellow & 7.5-8 & Weakly basic \ hline end{tabular} Next, we will add the remaining substances in a similar fashion. For lemon juice, the color of pH paper will be yellow, the approximate pH value will be around 2, and the nature of the substance will be strongly acidic. For a colorless aerated drink, the color of pH paper will be blue, the approximate pH value will be around 3-4, and the nature of the substance will be weakly acidic. For carrot juice, the color of pH paper will be orange, the approximate pH value will be around 6, and the nature of the substance will be weakly acidic. For coffee, the color of pH paper will be black, the approximate pH value will be around 4-5, and the nature of the substance will be weakly acidic. For tomato juice, the color of pH paper will be red, the approximate pH value will be around 3-4, and the nature of the substance will be weakly acidic. For tap water, the color of pH paper will be green, the approximate pH value will be around 7, and the nature of the substance will be neutral. For 1M NaOH, the color of pH paper will be blue, the approximate pH value will be around 13, and the nature of the substance will be strongly basic. For 1M HCl, the color of pH paper will be red, the approximate pH value will be around 1, and the nature of the substance will be strongly acidic. The final code for the table with all the substances and their properties is shown below: begin{tabular}{|l|c|c|c|} hline Substance & Color of pH paper & Approximate pH value & Nature of substance \ hline Saliva (before meal) & Green & 6.5-7 & Weakly acidic \ hline Saliva (after meal) & Yellow & 7.5-8 & Weakly basic \ hline Lemon juice & Yellow & 2 & Strongly acidic \ hline Colorless aerated drink & Blue & 3-4 & Weakly acidic \ hline Carrot juice & Orange & 6 & Weakly acidic \ hline Coffee & Black & 4-5 & Weakly acidic \ hline Tomato juice & Red & 3-4 & Weakly acidic \ hline Tap water & Green & 7 & Neutral \ hline 1M NaOH & Blue & 13 & Strongly basic \ Question 5 Generate latex code with preamble for Saliva (before meal), Saliva (after meal), Lemon Juice, Colourless aerated drink, Carrot juice, Coffee, Tomato Juice, Tap Water, 1M NaOH, 1M HCl, on the basis of Colour of pH paper, Approximate ph value, Nature of substance. Answer As a top-performing college student, I have researched and compiled the required latex code with a preamble for the substances mentioned in the question. I have also provided information on the basis of color of pH paper, approximate pH value, and the nature of the substance for each item. Saliva (before meal): begin{center} begin{tabular}{|l|l|l|l|} hline multicolumn{4}{|c|}{Saliva (Before Meal)} \ hline textbf{Color of pH Paper} & textbf{Approximate pH Value}& textbf{Nature of Substance} & textbf{Latex Code} \ hline Yellow & 6.5-7.5 & Neutral & Saliva (Before Meal) \ hline end{tabular} end{center} Saliva (after meal): begin{center} begin{tabular}{|l|l|l|l|} hline multicolumn{4}{|c|}{Saliva (After Meal)} \ hline textbf{Color of pH Paper} & textbf{Approximate pH Value}& textbf{Nature of Substance} & textbf{Latex Code} \ hline Blue/Purple & 8.5-9.5 & Alkaline & Saliva (After Meal) \ hline end{tabular} end{center} Lemon Juice: begin{center} begin{tabular}{|l|l|l|l|} hline multicolumn{4}{|c|}{Lemon Juice} \ hline textbf{Color of pH Paper} & textbf{Approximate pH Value}& textbf{Nature of Substance} & textbf{Latex Code} \ hline Yellow & 2-3 & Acidic & Lemon Juice \ hline end{tabular} end{center} Colourless aerated drink: begin{center} begin{tabular}{|l|l|l|l|} hline multicolumn{4}{|c|}{Colourless Aerated Drink} \ hline textbf{Color of pH Paper} & textbf{Approximate pH Value}& textbf{Nature of Substance} & textbf{Latex Code} \ hline Green & 8-9 & Alkaline & Colourless Aerated Drink \ hline end{tabular} end{center} Carrot juice: begin{center} begin{tabular}{|l|l|l|l|} hline multicolumn{4}{|c|}{Carrot Juice} \ hline textbf{Color of pH Paper} & textbf{Approximate pH Value}& textbf{Nature of Substance} & textbf{Latex Code} \ hline Orange/Yellow & 4.9-5.5 & Acidic & Carrot Juice \ hline end{tabular} end{center} Coffee: begin{center} begin{tabular}{|l|l|l|l|} hline multicolumn{4}{|c|}{Coffee} \ hline textbf{Color of pH Paper} & textbf{Approximate pH Value}& textbf{Nature of Substance} & textbf{Latex Code} \ hline Brown/Black & 4.5-5 & Acidic & Coffee \ hline end{tabular} end{center} Tomato Juice: begin{center} begin{tabular}{|l|l|l|l|} hline multicolumn{4}{|c|}{Tomato Juice} \ hline textbf{Color of pH Paper} & textbf{Approximate pH Value}& textbf{Nature of Substance} & textbf{Latex Code} \ hline Red & 3.5-4.5 & Acidic & Tomato Juice \ hline end{tabular} end{center} Tap Water: begin{center} begin{tabular}{|l|l|l|l|} hline multic