General Questions and Answers

Two isotopes would have which of the following being different from each other? I. number of protons II. number of neutrons III. mass number A. I only B. II only C. II and III only D. I and II only

The density of 20.0 g of potassium is 0.862 g/mL. What is the density of potassium in a 5.00 ng sample? Answer with correct sigsignificant figures. Units should be included and in the abbreviated form.

Write a balanced equation for the reaction described, using the smallest possible integer coefficients. Pure ammonium nitrate(NH4NO₂) undergoes a chemical change to form, dinitrogen monoxide and water.

What are the names of O3 and NH4+? A. trioxygen and ammonium B. ozone and ammonium C. ozone and ammonia D. trioxide and ammonia

You fill a rigid steel cylinder that has a volume of 20.0 L with nitrogen gas to a final pressure of 2.00 x 104 kPa at 28°C. How many kilograms of N₂ does the cylinder contain? Use the ideal gas law: P x V= n xRxT You will need to solve for the number of moles of N₂ in the cylinder, then convert the number of moles to kg of nitrogen. Use 3 significant figures and include the units for each answer. The molar mass of N₂ is 14.0 g/mol x 2 = Type your answer here. The temperature of the cylinder of N₂ is 28°C + 273 = Type your answer here. Next, rearrange the ideal gas law to isolate n as follows: n = (P x V)/(Rx T). Substitute the known quantities into the equation. Assume that R = 8.31 L* kPa/(K mol). How many moles of nitrogen are in the container? Type your answer here.

When H₂CO(g) reacts with O₂(g) to form CO₂(g) and H₂O(1), 135 kcal of energy are evolved for each mole of H₂CO(g) that reacts. Write a balanced equation for the reaction with an energy term in kcal as part of the equation. Use the SMALLEST INTEGER coefficients possible and put the energy term in an appropriate box. If a box is not needed, leave it blank.

In a chemical rection, an insufficient quantity of any of the reactants will limit the amount of product that forms. The _________ determines the amount of product that can be formed. The reactant that is not completely used up in a reaction is called the ________

0.9301 g sample of a compound known to contain C, H, and O was burned in oxygen to yield 1.729 g of CO2 and 0.3535 g of H₂O. CxHyOz. + O₂ ⇒ CO₂ + H₂O 1. What is the empirical formula? 2. What is the molecular formula of the compound if the molar mass of compound is 142 g/mol.

Which physical change is exothermic? A CO₂(s)→ CO₂(g) B. CO₂(1)→ CO₂(g) C. CO₂ (s)→ CO₂(1) D. CO₂(g) → CO₂ (s)

What is the formula for lead (IV) chromate? A. PbCrO4 B. Pb(CrO4)2 C. Pb₂(CrO4)2 D. Pb₂(CrO4)4

A hydrated salt is a solid that includes water molecules within its crystal structure. A student heated a 9.10-gram sample of a hydrated salt to a constant mass of 5.41 grams. What percent by mass of water did the salt contain? A. 3.69% B. 16.8% C. 40.5% D. 59.5%

Assuming ideal behaviors, what is the mass, in grams, of 95.2 mL of oxygen gas at STP? (Make sure to answer with the correct answer of significant figures and unit in the abbreviated form.)

Radio wave radiation falls in the wavelength region of 10.0 to 1000 meters. What is the frequency of radio wave radiation that has a wavelength of 565 m? Frequency= sec-1

The formula for silicon dioxide is SiO2. a. How many grams of silicon are present in 1.27 moles of silicon dioxide? grams b. How many moles of oxygen are present in 3.79 grams of silicon dioxide? moles

Given the incomplete equation representing an oxidation reaction: 2C4H10+ __O2 ⇒ 8CO2 + 10H₂0 What is the coefficient of O₂ when the equation is completely balanced using the smallest whole-number coefficients? A 3 B. 10 C. 13 D 7

Iron(III) oxide is the mineral used in the metallurgy of iron. The reaction below shows the reaction of Iron(III) oxide with carbon monoxide to extract iron. Fe₂O3(s) + 3CO(g) →2Fe(s) + 3CO₂(g) In the above reaction, how many grams of Fe2O3 are required to completely react with 84 grams of CO? A 64 grams B. 160 grams C. 80 grams D 1400 grams

Gaseous ethane (CH₂CH₂) will react with gaseous oxygen (O₂) to produce gaseous carbon dioxide (CO₂) and gaseous water (H₂O). Suppose 0.601 g of ethane is mixed with 1.3 g of oxygen. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to 2 significant digits.

Be sure to answer all parts. Carry out each of the following conversions. Report answers to appropriate number of significant figures. a. 0.96 kJ to cal

The compound manganese(11) bromide, MnBr, is soluble in water. Write the net ionic equation for the dissociation reaction that occurs when solid manganese(11) bromide dissolves in water: Be sure to specify states such as (aq) or (s). H₂0 |+| 4

What is the specific heat capacity (in units of J/g °C) of a substance if 2.41x104 J are needed to change the temperature of 187 g of it from 15.1 °C to 259.8 °C? Provide answer to 2 decimal places and do not include the unit. Do not use scientific notation.

For the following balanced reaction: Cu(s) + 2HCl(aq) → CuCl₂(aq) + H₂(g) How many grams of CuCl₂ will be produced from the reaction if one mole of Cu reacts with an excess of HCI? 1.0 133.7 2.0 267.4

the References to access important values if needed for this question. 0.520 mol sample of xenon gas at a temperature of 21.0 °C is found to occupy a volume of 22.5 liters. The pressure of this gas sample is ___ mm Hg.

Consider the dissolution of CaCl₂: CaCl₂ (s)→ Ca²+ (aq) + 2Cl(aq) ΔH = -81.5 kJ An 11.7-g sample of CaCl2 is dissolved in 126 g water, with both substances at 24.2°C. Calculate the final temperature of the solution assuming no heat loss to the surroundings and assuming the solution has a specific heat capacity of 4.18 J/°C-g. Temperature: °℃

Which of the following statements is true for ideal gases, but is not always true for real gases? Choose all that apply. Pressure is caused by molecule-wall collisions. Average molecular kinetic energy increases with temperature. The size of the molecules is unimportant compared to the distances between them. The volume occupied by the molecules is negligible compared to the volume of the container.

Which two sentences describe the demographic effects of the Agricultural Revolution? The percentage of the total population living in urban areas increased. The rural population increased steadily, while the urban population stabilized. The urban population increased steadily, while the total population stabilized. The percentage of the workforce employed in agriculture decreased. The percentage of the workforce employed in agriculture increased.

Gaseous methane (CH) will react with gaseous oxygen (O₂) to produce gaseous carbon dioxide (CO₂) and gaseous water (H₂O). Suppose 1.3 g of methane is mixed with 1.28 g of oxygen. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to 3 significant digits.

Science The concentration of hydrogen ions in household dish detergent is 10-12. What is the pH level of household dish detergent?

What volume is occupied by a 1.34 mol sample of neon gas at a temperature of 0 °C and a pressure of 1 atm? L

A31.5-g sample of water at 280. K. is mized with 50.2 g water at 310. K. Calculate the final temperature of the mixture assuming no heat loss to the surroundings. Temperature= K

Scientists are trying to find out why bees are dying in large numbers. Which best describes how the scientists will try to solve the problem? A. They will do the same experiments to obtain similar evidence. B. They will approach the problem in different ways but share ideas. C. They will only work with scientists who share the same opinions. D. They will observe the same patterns and draw the same conclusions.

For the following reaction, 4.57 grams of zinc oxide are mixed with excess water. The reaction yields 3.94 grams of zinc hydroxide. zinc oxide (s) + water (1) → zinc hydroxide (aq) What is the theoretical yield of zinc hydroxide ? __ grams What is the percent yield for this reaction ? __. %

Which equation represents a single replacement reaction? 2Al(s) + 3Cl₂(g) → 2AlCl3(s) 2Al(s) + 6HCl(aq) → 2AlCl3(aq) + 3H₂(g) 2AICI3(s) → 2Al(s) + Cl₂(g) AICI3(aq) + 3KOH(aq) → Al(OH)3(s) + 3KCl(aq)

Which statement describes the general trends in electronegativity and metallic properties as the elements in Period 2 are considered in order of increasing atomic number? 1. Both electronegativity and metallic properties decrease. 2. Both electronegativity and metallic properties increase. 3. Electronegativity decreases and metallic properties increase. 4. Electronegativity increases and metallic properties decrease.

A voltaic cell differs from an electrolytic cell in that in a voltaic cell 1. energy is produced when the reaction occurs 2. energy is required for the reaction to occur 3. both oxidation and reduction occur 4. neither oxidation nor reduction occurs

Be sure to specify states such as (aq) or (s). If a box is not needed leave it blank.. If no reaction occurs leave all boxes blank and click on "Submit". Use H for hydronium ion. Write a net ionic equation for the reaction that occurs when cobalt(II) carbonate (s) and excess hydrobrumic acid (aq) are combined.

Graph the parabola. y=x² +1 Plot five points on the parabola: the vertex, two points to the left of the vertex, and two to the right of the vertex. Then click on the graph-a-function

Read the following, and choose the correct answer. Ralph Waldo Emerson once wrote, "It is easy in the world to live after the world's opir solitude to live after our own; but the great man is he who in the midst of the cr perfect sweetness the independence of solitude." This quote can be best described as transcendentalism satire romanticism Unitarianism

6. 4 HNO3(aq) + Cu(s) Cu(NO3)2(aq) + 2 NO2(g) + 2 H₂O(/) List all substances in this reaction that are compounds: List all the substances in this reaction that are dissolved in water: Name a substance that is an element ("is in its elemental form"):

What does the below sentence contain? I rather recommend buying the children alive, and dressing them hot from the knife, as we do roasting pigs. Sarcasm Irony Satire Understatement

If a work is a critical success, like Kiss Me, Kate, this means it ___ earns little money receives negative reviews earns a lot of money receives positive reviews

Using molarity to A chemist adds 335.0 mL of a 0.0036 mmol/L calcium sulfate (CaSO4) solution to a reaction flask. Calculate the micromoles of calcium sulfate the chemist has added to the flask. Be sure your answer has the correct number of significant digits. μmol x10

What kind of conflict can a setting be a part of? Man vs. Society Man vs. Man Man vs. Self All of the choices

Define texture Dynamics, articulation and other factors that a composer may include in music that is meant to affect the listener. The amount of voices and how they work in cooperation with each other in a piece of music. Refers to the pattern of which a piece of music is composed. The loudness or softness of music

Write a net ionic equation for the overall reaction that occurs when aqueous solutions of potassium hydroxide and hydrosulfuric acid are combined Assume excess base.

A chemist adds 85.0 mL of a 0.0017 mM copper(II) fluoride (CuF₂) solution to a reaction flask. Calculate the micromoles of copper(II) fluoride the chemist has added to the flask. Be sure your answer has the correct number of significant digits.

10. The fruit fly represented in the diagram below has unusual, curled wings that formed after exposure to radiation. In order for the fly to pass this trait on to its offspring, a change had to occur in a. the blood cells of the fly b. the gametes of the fly c. all the body cells of the fly d. the muscles of the fly

A movie based on a play is a(n) adaptation example of plagiarism farce dramedy

A character walks out on stage. The audience laughs because he has a "Kick Mel" sign on his back. He whips around, confused by their laughter. Dramatic Irony Verbal Irony Platonic Irony None of the choices

Write a net ionic equation to show why solid lithium hydroxide, LiOH (s), forms a basic solution when it dissolves in water.

Using only the letter names of the spaces of the bass clef staff, which word below could be spelled? Cabbage Feed Fade Cage