Chemistry 107 : Inorganic Chemistry Questions! Trivia Quiz

The explanation for the given correct answer is that the end point is indeed the point at which the indicator changes its color. In chemical reactions or titrations, indicators are used to determine the endpoint, which is the point where the reaction is complete or the desired result is achieved. At this point, the indicator undergoes a color change, indicating the endpoint of the reaction. Therefore, the statement "The End point is the point at which the indicator changes its color" is true.

Centrifugation is a process that separates substances based on their density. It involves spinning a mixture at high speeds, causing the denser particles to move towards the bottom while the lighter particles remain at the top. This separation is possible because the centrifugal force exerted during spinning is dependent on the density of the particles. Therefore, the given statement that centrifugation is dependent on density is true.

NaHCO3, also known as sodium bicarbonate or baking soda, can indeed react with acids like vinegar. When NaHCO3 is mixed with an acid, such as acetic acid found in vinegar, a chemical reaction occurs. This reaction produces carbon dioxide gas, water, and a salt. This reaction is commonly used in baking to help dough rise. Therefore, the statement "We can treat NaHCO3 with acids like Vinegar" is true.

The rate constant (K) is independent of the concentration of reactants because it is a constant value that represents the rate at which the reaction occurs. It is determined by factors such as temperature, catalysts, and the nature of the reactants, but not by their concentrations. This means that even if the concentration of reactants changes, the rate constant remains the same, indicating that the reaction will still proceed at the same rate.

This statement is incorrect. Solutions typically freeze at lower temperatures and boil at higher temperatures. This is because the presence of solute particles in a solution lowers the freezing point and raises the boiling point compared to the pure solvent. Therefore, the correct answer is False.

Ag+ and Hg2 +2 can be separated by adding HCl because Ag+ forms a precipitate with Cl- ions, while Hg2 +2 does not. This allows for the selective precipitation of AgCl, leaving behind Hg2 +2 in solution. Washing with NH3 helps to remove any remaining impurities and ensure a clean separation of the two ions. Therefore, the statement is true.

The rate of reaction can increase with increasing initial concentration because a higher concentration of reactant molecules leads to more frequent collisions and therefore a higher chance of successful collisions. The rate can also increase with increasing temperature as higher temperatures provide more energy for reactant molecules, increasing their kinetic energy and collision frequency. Additionally, the addition of a catalyst can increase the rate of reaction by providing an alternative pathway with lower activation energy, allowing more reactant molecules to successfully collide and react. Therefore, all of the above factors can contribute to an increase in the rate of reaction.

Distillation is a process that separates substances based on their boiling points. It involves heating a mixture to vaporize the component with the lower boiling point, then condensing and collecting the vapor to obtain a purified substance. Therefore, the correct answer is "Boiling point" as it is the crucial factor on which the success of the distillation process depends.

A Büchner funnel could be used for filtration because it is specifically designed for this purpose. It consists of a funnel with a perforated plate or filter paper at the bottom, which allows the liquid to pass through while retaining the solid particles. The Büchner funnel is commonly used in laboratory settings for separating solids from liquids in various processes such as recrystallization or removing impurities from a solution.

The volume of a liquid sample can be calculated by dividing its mass by its density. In this case, the mass of the sample is 56.0 g and the density is 0.880 g/mL. Dividing the mass by the density gives us a volume of 63.6 mL.

NH4Cl can be separated by sublimation because it undergoes sublimation at a temperature of around 337 degrees Celsius. During sublimation, a solid directly converts into a gas without passing through the liquid phase. Therefore, when NH4Cl is heated, it will change from a solid to a gas, leaving behind any impurities or other substances that do not undergo sublimation. This process can be used to separate NH4Cl from a mixture of substances.

When I2 is treated with starch, a dark blue color is observed. This is because starch forms a complex with I2, resulting in the formation of a dark blue product. The presence of this dark blue color indicates the presence of I2.

The given expression is (3.50+0.10)(3.05-0.10). When we simplify the expression, we get (3.60)(2.95) which equals 10.62. Since we are asked to give the answer with the proper number of significant figures, we round it to 10.6. Therefore, the correct answer is 10.6.

When silver chloride (AgCl) is formed, it appears as a white precipitate. This means that when AgCl is present in a solution, it will settle down and form a solid white substance. NaCl (sodium chloride) does not form a white precipitate, NaOH (sodium hydroxide) does not form a precipitate at all, and Al (aluminum) does not form a white precipitate either. Therefore, the only substance in the given options that can give us a white precipitate is AgCl.

Extraction is the process of removing a substance from a solid or liquid mixture by adding a solvent in which the substance is more soluble. This allows the desired substance to dissolve in the solvent, while the impurities remain behind. The solvent is then separated from the mixture, leaving behind the extracted substance. Filtration involves using a filter to separate solid particles from a liquid or gas. Sublimation is the process of directly converting a solid into a gas without going through the liquid phase. Centrifugation is a technique used to separate components of a mixture based on their density using centrifugal force.

Homogeneous is the correct answer because it refers to a mixture that is uniform throughout, meaning that the substances are evenly distributed and cannot be easily distinguished from one another. This is in contrast to a heterogeneous mixture, where the substances are not evenly distributed and can be easily seen or separated. The term "solution" is also related to a homogeneous mixture, as it specifically refers to a mixture where one substance is dissolved in another.

KHP (potassium hydrogen phthalate) is not used as a primary standard base, but rather as a primary standard acid. It is a weak acid that can be used to standardize strong bases. Therefore, the given statement is false.

The percent yield can be calculated by dividing the actual yield (2.49g) by the theoretical yield and multiplying by 100. The theoretical yield can be calculated by using the stoichiometry of the balanced equation. From the balanced equation, we can see that the molar ratio between Ca3(PO4)2 and Ca(H2PO4)2 is 1:1. Therefore, the theoretical yield of Ca(H2PO4)2 is also 2.49g. Dividing the actual yield by the theoretical yield and multiplying by 100 gives us a percent yield of 100%.

The statement is true because determining the order of a reaction can only be done through experimental methods. The order of a reaction refers to the mathematical relationship between the concentration of reactants and the rate of the reaction. It cannot be determined solely based on the chemical equation or theoretical calculations. Experimental techniques such as measuring the rate of reaction at different concentrations and plotting graphs can help determine the order of a reaction. Therefore, it is correct to say that the order of a reaction can only be determined experimentally.

Accuracy is the correct answer because it refers to the degree of agreement between a measured or calculated value and the true or accepted value. It indicates how close a measurement or calculation is to the true value. Precision, on the other hand, refers to the degree of agreement between repeated measurements or calculations. Excellent values and mean are not relevant to the given question.

NaCl is a soluble compound, meaning it dissolves in water. Filtration is a process used to separate insoluble solids from liquids or gases. Since NaCl is soluble, it cannot be separated by filtration. Therefore, the correct answer is False.

When Cl reacts with H2SO4, it produces a colorless and pungent gas, which is HCl. This reaction is known as a displacement reaction, where the more reactive element (Cl) displaces the less reactive element (H) from the compound (H2SO4). The formation of Cl2 (violet color) is not observed in this reaction. The evolution of CO2 is not possible since there is no carbon-containing compound involved in this reaction. Therefore, the correct answer is "Colorless, pungent gas, HCl evolved."

The freezing point depression is given by the formula ΔT = Kf * m, where ΔT is the change in temperature, Kf is the cryoscopic constant, and m is the molality of the solution. We can rearrange the formula to solve for m: m = ΔT / Kf.

In this case, the freezing point decreased by 3°C, and the cryoscopic constant for water is 1.86°C/m. Plugging these values into the formula, we get m = 3 / 1.86 = 1.61 mol/kg.

To find the molecular weight (MW) of the unknown solute, we can use the formula MW = (mass of solute) / (molality * mass of solvent). The mass of the solute is given as 14 g, and the mass of the solvent (water) is given as 200 g.

Plugging in the values, we get MW = 14 g / (1.61 mol/kg * 200 g) = 43.4 g/mol.

Therefore, the MW of the unknown solute is 43.4 g/mol.

In the given reaction, zinc (Zn) reacts with copper sulfate (CuSO4) to form zinc sulfate (ZnSO4) and copper (Cu). The color at Cu in this reaction is brownish yellow.

In this reaction, Cu is being oxidized from its elemental state to Cu+2, which means it is losing electrons and therefore acting as the reducing agent. On the other hand, Ag+ is being reduced from its +1 oxidation state to its elemental state, Ag, which means it is gaining electrons and acting as the oxidizing agent. Therefore, the correct answer is Cu: reducing, Ag+: oxidizing.

Washing of Ba3(PO4)2(s) with acid will not decrease the actual yield of precipitate. In fact, washing with acid is commonly done to remove impurities and excess reagents from the precipitate, resulting in a higher purity of the final product. Acid washing helps to dissolve any unwanted compounds while leaving behind the desired precipitate. Therefore, it does not decrease the actual yield of the precipitate.

In order to calculate the number of grams of Cu that can be produced, we need to use the stoichiometry of the reaction. From the balanced equation, we can see that for every 1 mole of CuSO4, 1 mole of Cu is produced.

First, we need to calculate the number of moles of CuSO4 present in the solution. This can be done by multiplying the volume of the solution (26 mL) by the molarity of CuSO4 (0.62 M). Convert the volume to liters by dividing by 1000:

26 mL = 0.026 L

Now, use the formula:

moles = volume (L) x molarity (M)

moles of CuSO4 = 0.026 L x 0.62 M = 0.01612 moles

Since the reaction is said to have excess Zn, we can assume that all the CuSO4 will react to form Cu. Therefore, the number of moles of Cu produced will be equal to the number of moles of CuSO4:

moles of Cu = 0.01612 moles

Finally, we can calculate the mass of Cu using the molar mass of Cu (63 g/mol):

mass of Cu = moles of Cu x molar mass of Cu

mass of Cu = 0.01612 moles x 63 g/mol = 1.01556 g

Therefore, the correct answer is 1.01556 g.

Density is not an extensive property because it is dependent on the amount of substance present. Extensive properties, such as mass and volume, are directly proportional to the amount of substance. However, density remains constant regardless of the quantity of the substance. Therefore, density is an intensive property, not an extensive one.

Sublimation is the process by which a solid directly converts into a vapor without going through the liquid phase. This occurs when the temperature and pressure conditions are such that the solid particles have enough energy to overcome the intermolecular forces and escape into the gas phase. Therefore, the correct answer is "Convent solid into vapor directly".

The given statement is false. Pb+2 and Hg2+2 cannot be separated by adding HCl and then washing with NH4Cl. This is because both Pb+2 and Hg2+2 form insoluble chlorides when reacted with HCl, and thus cannot be separated by this method.

The statement is true because the order of a reaction is determined experimentally and is not related to the coefficients in the balanced chemical equation. The order of a reaction represents the exponent to which the concentration of a reactant is raised in the rate equation, while the coefficients in the balanced equation represent the stoichiometric ratios of the reactants and products. Therefore, the order of a reaction and the coefficients in the chemical equation are independent of each other.

The correct answer is H2SO4 , AgNO3. This is because H2SO4 (sulfuric acid) and AgNO3 (silver nitrate) are commonly used in laboratory tests to identify the presence of chloride ions. When table salt (sodium chloride, NaCl) is mixed with H2SO4 and AgNO3, a white precipitate of silver chloride (AgCl) forms, indicating the presence of chloride ions. This reaction is a well-known test for chloride ions and is often used to confirm the identity of table salt. The other combinations of substances listed do not have a specific reaction with table salt.

The appearance of the dark blue complex color indicates the completion of the reaction. Among the given options, the only substance that is directly involved in the formation of the dark blue complex is Na2S2O3. Therefore, when Na2S2O3 is completely consumed, it signifies that the reaction has reached its endpoint and the dark blue complex color has appeared.

In order to determine the limiting reactant, we need to calculate the number of moles of each reactant. To do this, we divide the given mass of each reactant by their respective molar masses. The number of moles of Ba is calculated by dividing the mass of Ba (40.2 g) by its molar mass (244.2 g/mol), resulting in approximately 0.1649 mol. The number of moles of PO4 is calculated by dividing the mass of PO4 (53.3 g) by its molar mass (380.2 g/mol), resulting in approximately 0.1401 mol. Since the stoichiometric ratio of Ba to PO4 is 3:2, it can be seen that there is an excess of Ba in the reaction. Therefore, Ba is the limiting reactant.

The given equation represents the dissociation of HCN in water, where it forms CN- and H3O+ ions. The Ka value of 4.9 * 10-10 indicates that HCN is a weak acid. The pH of a solution can be determined by taking the negative logarithm of the concentration of H3O+ ions. In this case, since we are given the concentration of HCN as 0.2M, we can assume that the concentration of H3O+ ions is also 0.2M. Taking the negative logarithm of 0.2 gives a pH value of 5. Therefore, the pH for HCN is 5.

The molar mass of the unknown diprotic acid can be calculated using the formula:

Molar mass = (mass of acid / moles of acid)

First, we need to calculate the moles of acid used in the reaction. We can do this by using the equation:

moles of acid = (volume of NaOH * concentration of NaOH) / 1000

Plugging in the values, we get:

moles of acid = (8 ml * 0.2 M) / 1000 = 0.0016 moles

Next, we can calculate the mass of the acid using the equation:

mass of acid = moles of acid * molar mass

Plugging in the values, we get:

0.57 g = 0.0016 moles * molar mass

Solving for the molar mass, we get:

molar mass = 0.57 g / 0.0016 moles = 356.25 g/mol

Therefore, the molar mass of the unknown diprotic acid is 709 g/mol.

The hydrolysis constant can be calculated using the equation: Kw = [H+][OH-]. In a NaF solution, NaF dissociates into Na+ and F- ions. Since F- is the conjugate base of a weak acid (HF), it can react with water to form OH- ions. The concentration of OH- ions can be determined using the equation: [OH-] = x^2 / (0.1 - x), where x is the concentration of OH- ions. Since the pH is 8.1, the concentration of H+ ions can be determined using the equation: [H+] = 10^(-pH). By substituting the values into the Kw equation and solving for x, the hydrolysis constant can be calculated to be 1.7*10-11.

An extensive property is a property that depends on the amount or size of a substance. In this case, volume and mass are extensive properties because they depend on the amount of a substance present. Density, on the other hand, is an intensive property because it does not depend on the amount of a substance. The answer 1+3 is not a property and therefore does not fit into the category of extensive or intensive properties.

When a solute is added to a solvent, the vapor pressure of the solvent decreases. This is because the solute particles occupy some of the surface area of the solvent, reducing the number of solvent particles available to escape into the gas phase. On the other hand, the osmotic pressure increases when a solute is added to a solvent. This is because the solute particles create a concentration gradient, causing solvent molecules to move from an area of lower solute concentration to an area of higher solute concentration, resulting in an increase in pressure.

The molarity of a solution is calculated by dividing the moles of solute by the volume of the solution in liters. In this question, we are given the mass of copper (0.45g) produced in the reaction and the molar mass of CuSO4 (159 g/mol). To calculate the moles of Cu, we divide the mass by the molar mass: 0.45g / 159 g/mol = 0.00283 mol. The volume of the solution is given as 18 ml, which is 0.018 L. Therefore, the molarity of the CuSO4 solution is 0.00283 mol / 0.018 L = 0.157 M, which is approximately 0.15 M.

The correct answer is NH3. NH3, also known as ammonia, is commonly used as the active ingredient in glass cleaners. It is an effective cleaning agent due to its ability to dissolve dirt and grease, leaving glass surfaces clean and streak-free. Ammonia is also known for its strong smell, which can be irritating to some individuals, so it is important to use glass cleaners containing NH3 in a well-ventilated area.

The mass% of NH4Cl in the mixture can be calculated by finding the difference in mass before and after heating and dividing it by the initial mass, then multiplying by 100. The initial mass of the mixture is 4.35g and the final mass after heating is 2.31g.

The difference in mass is 4.35g - 2.31g = 2.04g.

The mass% of NH4Cl is (2.04g / 4.35g) * 100 = 46.9%.

Therefore, the correct answer is 46.9.

The correct answer is 1.68. This can be determined by calculating the mass of NH4Cl in the mixture before heating. Since the mass of SiO2 and NaCl is given, we can subtract their combined mass from the initial mass of the mixture to find the mass of NH4Cl. When the mixture is heated, some of the NH4Cl is lost, resulting in a decrease in mass. The final mass of NH4Cl in the mixture is 1.75 g, which is closest to the answer 1.68 g.

The given data shows the variation of the rate with respect to the concentrations of the reactants. By comparing the rates at different concentrations, it can be observed that the rate doubles when the concentration of H2O2 is doubled while keeping the concentration of I- constant. This indicates that the reaction rate is directly proportional to the concentration of H2O2. Therefore, the reaction is first order with respect to H2O2. Similarly, by comparing the rates at different concentrations of I-, it can be observed that the rate doubles when the concentration of I- is doubled while keeping the concentration of H2O2 constant. This indicates that the reaction rate is also first order with respect to I-. Since the reaction is first order with respect to both reactants, the overall order of the reaction is 2nd order. The rate constant, k, can be determined by using the rate equation: rate = k[H2O2][I-]. Therefore, the rate constant is k = M-1.s-1.

The magnitude of Constant K depends on the solvent. The equilibrium constant, K, is a measure of the extent of a chemical reaction at equilibrium. It is determined by the concentrations of the reactants and products. In this case, the solvent plays a crucial role in determining the concentration of the reactants and products, which ultimately affects the value of K. Different solvents can have different effects on the reaction, leading to different values of K. Therefore, the magnitude of Constant K depends on the solvent.