General Questions and Answers

The Middle Ages covers the years 1750-1820 1820-1900 1450-1600 450-1450

An object is said to be at rest, if it does not change its its surroundings. displacement velocity position acceleration with respect to a reference point or

One cup of kidney beans contains 15 g of protein, 1 g of fat, and 42 g of carbohydrate. How many kilocalories, to two significant figures, does this sample contain? (The caloric values are: 4 kcal/g for carbohydrate, 9 kcal/g for fat, and 4 kcal/g for protein.) 230 kcal 88 kcal 520 kcal 60. kcal O240 kcal

An iron nail rusts when exposed to oxygen. According to the following reaction, how many grams of oxygen gas are required for the complete reaction of 32.1 grams of iron? 4Fe (s) + 30₂ (g)-2Fe₂O₂ (s) __ grams oxygen gas.

A dose of aspirin of 5.0 mg per kilogram of body weight has been prescribed to reduce the fever of an infant weighing 8.5 pounds. The number of milligrams of aspirin that should be administered is ___. Given 1lb = 454 g.

Consider the following system at equilibrium at 1150 K: 2 SO3(g)__ 2 SO₂ (g) + O₂ (g) When some SO₂ (g) is removed from the equilibrium system at constant temperature: The reaction must: A. Run in the forward direction to reestablish equilibrium. B. Run in the reverse direction to reestablish equilibrium. C. Remain the same. It is already at equilibrium. The concentration of O₂ will: A. Increase. B. Decrease. C. Remain the same.

Listed below are some elements. Identify the nonmetal element. Sodium, sulfur, calcium, and cadmium. Cadmium Sodium Sulfur Calcium

Write the net ionic equation for any reaction that may be predicted when aqueous solutions of zinc sulfate and chromium(II) nitrate are combined.

Calculate ΔHrxn for the process CO3O4 (s) -> 3 Co (s) + 2 O₂ (g) from the following information: Co (s) + 1/2 O2 (g) --> CoO (s) ΔH = -237.9 kJ 3 CoO (s) + O₂ (g) -> CO3O4 (s) ΔH = -177.5 kJ

Consider reaction: 2Fe(s) + 3Cl2(g) ⇒ 2FeCl3(s) If 22.0 g of Fe and 33.0 g of Cl2 are combined, which compound is the Limiting Reagent and what is the theoretical yield of FeCl3 in grams? Molar masses: Fe = 55.845 g/mole; Cl2 = 70.90 g/mole; FeCl3 = 162.2 g/mole Limiting Reagent is [a] The theoretical yield of FeCl3 is [b] g. Specified Answer for: a Specified Answer for: b

Starting with Michaelis Menten equation explain how "kcat/Km represents an apparent second-order rate constant"

Assuming ideal behaviors, what is the pressure, in atm, of 71.5 g of CO2(g) (MW = 44.01) in a 173.5 mL rigid, sealed flask at 46.8 °C? Given: R = 0.0821 atm L-mole-1.K-1. Answer in correct significant figures and unit in the abbreviated form. Do not answer in scientific notation.

Be sure to answer all parts. For the following aqueous reaction, complete and balance the molecular equation and write a net ionic equation, making sure to include the physical states of the compounds: calcium hydroxide + nitric acid Net ionic equation:

Convert grams of propane to kilocalories of energy. Select the correct units and conversion factors for each step in the following unit roadmap. C3H8 (9) +502 (9) 3 CO2 (g) + 4 H₂0 (l) Δ=-531 kcal/mol g C3H₂ ⇒ ___ ⇒kcal 44.1 g/1 mol mol C3 H8 mol H₂ O 531 kcal/1 mol mol CO₂ 1 mol/44.1 g mol O₂

Enter your answer in the provided box. Calculate the following quantity: molarity of a solution prepared by diluting 59.30 mL of 0.0320 M ammonium sulfate to 550.00 mL.

Enter your answer in the provided box. If 45.9 mL of silver nitrate solution reacts with excess potassium chloride solution to yield 0.210 g of precipitate, what is the molarity of silver ion in the original solution?

How many grams of iron are needed to react with 35 g of chlorine to produce 63 g of iron(II) chloride? Fe + Cl₂ → FeCl₂

Density is a physical property of a molecule that's measured as mass per unit volume. (a) Given that density is usually expressed in the units of g/cm³, calculate the density of a cube of plastic that has a mass of 2.331 g and an edge length of 1.500 cm (volume of a cube is V=P³).

Using average bond enthalpies (linked above), estimate the enthalpy change for the following reaction: C₂H6(g) + Cl₂(g)C₂H5Cl(g) + HCl(g)

Be sure to answer all parts. Classify each process as exothermic or endothermic: freezing of water boiling of water break down of food during digestion a person running a person growing turning graphite into diamond heating with a furnace

Classify the following as acid-base reactions or oxidation-reduction reactions: K3P(s) + 202(g) → K3PO4(s) If the reaction is an acid-base reaction, express which one corresponds acid and base. If the reaction is a redox reaction, express which one undergoes oxidation or reduction. acid-base reaction / K3P is an acid and O2 is a base. acid-base reaction / K3P is a base and O2 is an acid. oxidation-reduction reaction / K atom (of K3P) undergoes oxidation and O atom (of O2) undergoes reduction. oxidation-reduction reaction / O atom (of O2) undergoes oxidation and P atom (of K3P) undergoes reduction. oxidation-reduction reaction / O atom (of O2) undergoes reduction and P atom (of K3P) undergoes oxidation.

(Use "Activity Series of Metal" in the formula sheet of Blackboard) Based on the activity series, which one of the reactions below will occur? 1.Fe (s) + ZnCl2 (aq) -> FeCl2 (aq) + Zn (s) 2. Mn (s) + NiCl2 (aq) → MnCl2 (aq) + Ni (s) 3. Pb (s) + Nil2 (aq) ->PbI2 (aq) + Ni (s) 4. SnBr2 (aq) + Cu (s) ->CuBr2 (aq) + Sn (s) 5. None of the reactions will occur.

Which one corresponds to the limiting reagent when 0.20 mol of P4 and 0.20 mol of O2 react according to the following balanced equation? P4 (S) +502 (g) → P4O10 (S) P4 (F.W 123.9 g/mol), O2 (F.W=32 g/mol), P4010 (F.W= 141.94 g/mol) = P4010 P4 Both P4 and P4010 O2 Both O2 and P4010

Draw all resonance structures for the nitryl fluoride molecule, NO₂F. Explicitly draw all H atoms. Include all valence lone pairs in your answer. Do not include overall idn charges or formal charges in your drawing. Do not draw double bonds to oxygen unless they are needed for the central atom to obey the octet ru Draw one structure per sketcher. Add additional sketchers using the drop-down menu in the bottom Separate resonance structures using the symbol from the drop-down menu.

For the following aqueous reaction, complete and balance the molecular equation and write a net ionic equation, making sure to include the physical states of the compounds: barium acetate + iron(II) sulfate Molecular equation: Net ionic equation:

One way of obtaining pure sodium carbonate is through the decomposition of the mineral trona, Na3(CO3)(HCO3).2H₂O. 2Na3(CO3)(HCO3)-2H₂O(s) -> 3Na2CO3(s) + CO2(g) + 5H₂O(g) When 1.00 metric ton (1.00 103 kg) of trona is decomposed, 0.650 metric ton of Na2CO3 is recovered. What is the percent yield of this reaction? 72.1% 92.4% 48.1% 65.0% 35.0%

A mixture of sand and salt is found to be 48 percent NaCl by mass. How many moles of NaCl are in 74 grams of this mixture?

An atomic anion with a charge of -3 has the following electron configuration: 1s²2s²2p 3s²3p6 What is the chemical symbol for the ion? How many electrons does the ion have? How many 3s electrons are in the lon?

A hydrocarbon has a mass percent composition of 88.80% carbon and 11.20% hydrogen. When a sample of this hydrocarbon with a mass of 14.78 g is vaporized in a sealed container with a volume of 4.00 L and heated to 120.0°C, the pressure in the flask is 223 kPa. (a) Determine the empirical formula of the compound. [3A] (b) Determine the molar mass of the compound. [2A] (c) Determine the molecular formula of the compound. [2A]

An organic compound is analyzed and found to be 54.9 % carbon, 9.80% hydrogen and 38.30% chlorine. What is the empirical formula of this compound?

Select the correct answer. What does the expression "75 meters per second southeast" best describe? A acceleration B. distance C. speed D. velocity

A student reads a barometer in the laboratory and finds the prevailing atmospheric pressure to be 741 mmHg. Express this pressure in torr and in atmospheres. Hint: 1 atm = 760 mmHg = 760 torr Pressure = Pressure = torr atm

Give the oxidation number of carbon in the following: (a) HCO3 ___ (b) Na₂C₂04 ___ (c) CF₂Cl₂ ___ (d) C₂H6 ____

a) Write the balanced ionic equation for the dissociation of the salt. b) Write an equation to show the hydrolysis of both the cation and anion of the salt. c) Predict if the aqueous solution of the salt is basic, acidic or neutral. Explain using the chemical equations above, and Ka and Kb values. (NH4)2SO4 KHCO3

5. A reaction between sodium borate and acetic acid is a neutralization reaction (just like a reaction between sodium bicarbonate and acetic acid is a neutralization reaction). Also just like in the reaction that you performed in this lab, all the reactants and products are colorless. The reaction equation is Na3BO3(aq) + 3 CH3COOH(aq) → 3 CH3COONa(aq) + H3BO3(aq) Although those two reactions are similar, the one with sodium borate cannot be performed if you follow the experimental procedure in this lab handout. Select the best explanation for that from the list below. a) The chemical equation is not balanced. b) It is not possible to detect the point when the reaction is completed, and you should stop adding vinegar (if you follow the procedure as it is written in this handout). c) The reaction is very slow: you will not be able to complete the lab in a reasonable time period. d) It is not safe to perform this reaction at home.

Be sure to answer all parts. An auto mechanic spills 93 mL of 2.8 M H₂SO4 solution from a rebuilt auto battery. How manymilliliters of 1.4 M NaHCO3 must be poured on the spill to react completely with the sulfuric acid? __x 10__ mL (Enter your answer in scientific notation.)

Be sure to answer all parts. How many moles and numbers of ions of each type are present in the following aqueous solution? 83.7 mL of 1.55 M magnesium chloride: mol of magnesium magnesium ions mol of chloride chloride ions

A penny has a mass of 2.50 g and the Moon has a mass of 7.35 × 10²2 kg. Use this information to answer the questions below. Be sure your answers have the correct number of significant digits. What is the mass of 1 mole of pennies? Round your answer to 3 significant digits. How many moles of pennies have a mass equal to the mass of the Moon? Round your answer to 3 significant digits.

Suppose 2.37 g of sodium chloride is dissolved in 200. mL of a 41.0 m M aqueous solution of silver nitrate. Calculate the final molarity of chloride anion in the solution. You can assume the volume of the solution doesn't change when the sodium chloride is dissolved in it. Round your answer to 3 significant digits.

What is the net ionic equation in the reaction when mixed Kl(aq) and AgNO3(aq)? K+ (aq) + (aq) + Ag*(aq) + NO3(aq) → K*(aq) + NO3(aq) + (aq) + Ag*(aq) I-(aq) + Ag+ (aq) → Agl (s) NO3(aq) + K+ (aq) → KNO3(aq) KI (aq) + AgNO3(aq) → KNO3(aq) + Agl (s) K+ (aq) + (aq) + Ag (aq) + NO3(aq) → K*(aq) + NO3(aq) + Agl (s)

Solve the formula for the specified variable. A = P + Prt; P (business) A formula is an equation that expresses known relationships between two or more variables. We are asked to solve the formula A = P + Prt for the specified variable

Hypothesis 2: If you increase the particle size of a reactant, then the reaction rate will increase because more of the reactants' molecules will contact each other. To test the second hypothesis, you measured the reaction rate for several different

F. Consider the following two thermochemical equations: N2(5) + 5/2O2(g) N₂O5(s) ΔH = x kJ N2(g) + 5/2O2(g) → N₂O5(g) ΔH = y kJ The enthalpy change, in kJ, for the sublimation of one mole of N₂O5 solid to gas would be represented by the quantity: (A) x + y (B) x - y (C) y - x (D)-x-y (E) xy

The formula for phosphorus triiodide is PI3. a. How many grams of phosphorus are present in 4.15 moles of phosphorus triiodide? grams b. How many moles of iodine are present in 2.26 grams of phosphorus triiodide? moles

Ammonia (NH3) combines with oxygen according to the balanced equation below. What is the limiting reactant if 2.75 moles of NH3 combines with 2.15 moles of O₂? 4 NH3 +3 02 → 2 N₂ + 6H₂O

The compound cobalt(II) fluoride, CoF, is soluble in water. Write the net ionic equation for the dissociation reaction that occurs when solid cobalt(II) fluoride dissolves in water: Be sure to specify states such as (aq) or (s).

The compound ammonium sulfate, (NH₂),SO, is soluble in water. Write the net ionic equation for the dissociation reaction that occurs when solid ammonium sulfate dissolves in water: Be sure to specify states such as (aq) or (s).

When a balloon is submerged into ice water at constant pressure, A. the volume will decrease B. the volume will increase C. the pressure will increase D. the number of gas particles will decrease

Calcium hydroxide reacts with aqueous sodium carbonate to produce sodium hydroxide and calcium carbonate. a) Write a balanced equation for it. b) What mass of sodium hydroxide is produced when 175.0 g of calcium hydroxide is completely reacted in an excess of sodium carbonate?

What is the mole ratio when the following pairs of acids and bases combine in neutralization reactions? Fill in the blanks as you answer the question. HCI and Sr(OH)₂ H₂SO and NaOH H₂PO4 and KOH HNO3 and LIOH