Classification of Elements and Periodicity Questions and Answers

Hydrogen peroxide is used as a cleaning agent in the treatment of cuts and abrasions for several reasons. It is an oxidizing agent that can directly kill many microorganisms; it decomposes upon contact with blood, releasing elemental oxygen gas (which inhibits the growth of anaerobic microorganisms); and it foams upon contact with blood, which provides a cleansing action. In the laboratory, small quantities of hydrogen peroxide can be prepared by the reaction of an acid on an alkaline earth metal peroxide, such as barium peroxide. BaO2 (s) + HCl(aq) → H₂O₂ (aq) + BaCl₂ (aq) What amount of hydrogen peroxide should result when 1.18 g of barium peroxide is treated with 26.7 ml of hydrochloric acid solution containing 0.0283 g of HCI per mL?

If a gas at 0.832 atm pressure in a volume of 0.565 L is compressed to 0.195 L, what is the new pressure according to the ideal gas law? 0.287 atm 2.41 atm 3.48 atm 0.415 atm

In a gas thermometer (constant pressure conditions) the gas has a volume of 1.00 L at 85.0 °C. The thermometer is placed in a freezer. The final volume measured is 0.29 L. What is the temperature of the freezer? 100 K 25 K 1.2×10³ K 3.4×10-³ K

The modern periodic table has the elements arranged in order of increasing A. density. B. atomic size . C. atomic weight. D. atomic number. E. charge.

What would you multiply "moles of strontium" by to get the units "grams of strontium"?

Many metals occur naturally as sulfide compounds; examples include ZnS and CoS. Air pollution often accompanies the processing of these ores, because toxic sulfur dioxide is released as the ore is converted from the sulfide to the oxide by roasting (smelting). For example, consider the unbalanced equation for the roasting reaction for zinc: ZnS (s) + O₂(g) → ZnO(s) + SO2(g) How many kilograms of sulfur dioxide are produced when 240 kg of ZnS is roasted in excess oxygen by this process?

For the following reaction, 5.21 grams of magnesium nitride are mixed with excess water. The reaction yields 7.00 grams of magnesium hydroxide. magnesium nitride (s) + water (I) → magnesium hydroxide (aq) + ammonia (aq) What is the theoretical yield of magnesium hydroxide? What is the percent yield of magnesium hydroxide?

Classify each of the compounds as soluble or not soluble: magnesium sulfate aluminum hydroxide calcium carbonate

On the basis of the element's location in the periodic table, indicate what simple ion each of the following elements is most likely to form. Cl a. Formula of ion: Ra b. Formula of ion: Ca c. Formula of ion:

How many of the following postulates of Dalton's atomic theory are still scientifically accepted? I. All atoms of the same element are identical. II. Compounds are combinations of different atoms. III. A chemical reaction changes the way atoms are grouped together. IV. Atoms are indestructible. 1 0 4 3 2

The element rubidium forms a ____ with the charge ____ The symbol for this ion is ___ The number of electrons in this ion is and the name is ___

Consider the following reaction: CH₂(g) +40₂(g) →CCl₂(g) + 4HCl (g) What mass of CCl4 will be formed if 1.20 moles of methane react with 1.07 moles of chlorine? 41.1 g 658 g 185 g 165 g 19.0 g

Naturally occurring element X exists in three isotopic forms: X-28 (27.977 amu, 92.23% abundance), X-29 (28.976 amu, 4.67% abundance), and X-30 (29.974 amu, 3.10% abundance). What is the identity of element X? Al Sr Cu Ni Si

e. Choose an example of a synthesis reaction that is also an oxidation-reduction reaction, but that does not involve combustion. 2KNO3(s) → 2KNO2 (s) + O2(g) 2Fe(s) + 3Cl2 (g) → 2FeCl3 (s) 2AgNO3 (s) → 2Ag(s) + 2NO2(g) + O₂(g) CH4 (g) +202 (g) → CO2 (g) + 2H₂O(l) NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(1) C(s) + O₂(g) → CO2 (g)

Choose the characteristic physical properties that distinguish the metallic elements from the nonmetallic elements. (Select all that apply.) rigid and fragile bad conductors of electricity bad conductors of heat excellent conductors of electricity generally shiny (lustrous) when a fresh surface is exposed excellent conductors of heat malleable and ductile generally transparent when polished

How many protons and neutrons are contained in the nucleus of the isotopes below? Assuming the atoms are uncharged, how many electrons are present? 22Ti48 protons neutrons electrons 56fe26 protons neutrons electrons

a. Give the correct definition of a combustion reaction. A combustion reaction is typically a reaction in which an element or compound reacts with so quickly and with such a large release of energy that a flame results. b. In addition to the chemical products, what other products do combustion reactions produce? electrons atoms heat energy protons c. Write the chemical equation for a combustion reaction of C₂H6. (Use the lowest possible coefficients. Omit states of matter.)

A compound containing only sulfur and phosphorus is 50.9% S by mass; the molar mass is 252 g/mol. What are the empirical and molecular formulas of the compound? Empirical formula: Molecular formula:

Complete the balanced equation for the reaction that produces the given salt. (Use the lowest possible coefficients. Be sure to specify states such as (aq) or (s). If a box is not needed, leave it blank.) a. __ + __ -> __ Rb2SO4 (aq) + __H2O (l) a. __ + __ -> __CsNO3 (aq) + __H2O (l) a. __ + __ -> __ RbCl (aq) + __H2O (l)

A compound is found to contain 34.60 % chlorine, 46.85 % oxygen, and 18.55 % fluorine by mass. The empirical formula for this compound is The molar mass for this compound is 102.5 g/mol. The molecular formula for this compound is

An element consists of 0.19% of an isotope with mass 135.907 u, 0.25% of an isotope with mass 137.9060 u, 88.45% of an isotope with mass 139.9054 u, and 11.11% of an isotope with mass 141.9092 u. Calculate the average atomic mass, and identify the element.

Write the net ionic equation for the following molecular equation. Ag₂SO4(aq) + (NH4)2CO3(aq) → Ag₂CO3(s) + (NH4)2SO4(aq)

Calculate (Show all work for credit. Answer should be in significant figures) a. How many meters in 1.00 mile? b. How many centimeters are in 2.00 ft?

Which BEST explains how syllogisms should be used to prove logic? Select one: arrange statements that avoid using emotional logic arrange arguments that avoid using ethos or pathos arrange premises so only one true conclusion is possible arrange fallacies so only one true conclusion is possible

Select the net ionic equation for the following reaction: NaCl(aq) + AgNO3(aq) -> NaNO3(aq) + AgCl(s) Ag (aq) + Cl(aq) -> AgCl(s) Ag(s) + Cl(g) -> AgCl(s) Ag (aq) + NO3(aq) + Nat(aq) + Cl(aq) -> AgCl(s) + Na*(aq) + NO3(aq) AgNO3(aq) + CH(aq) -> AgCl(s) + NO3(aq) NaCl(aq) + Ag*(aq) -> AgCl(s)

The aspirin substitute, acetaminophen (C8H₂O₂N), is produced by the following three-step synthesis: i. C6H5O3N(s) + 3H₂(g) + HCl(aq) → CeHs ONCI(s) + 2H₂O(l) ii. C, H, ONCI(s) + NaOH(aq) → C6H7 ON (s) + H₂O(l) + NaCl(aq) iii. C&H7 ON (s) + C₂H6O3(1)→ Cg H₂O₂N(s) + HC₂H30₂ (l) The first two reactions have percent yields of 86% and 94% by mass, respectively. The overall reaction yields 13 moles of acetaminophen product for every 17 moles of C6H5O3N reacted. a. What is the percent yield by mass for the overall process? b. What is the percent yield by mass of Step III?

Which of the following compounds is a non-electrolyte? A.acetic acid, CH3CO₂H B.iron(II) chloride FeCl2 C.potassium iodide, Kl D.sodium bicarbonate, NaHCO3 E.iodine

The term brinkmanship refers to: a. willingness to interfere with the national bank. b. willingness to go to the edge, or brink, of war. c. willingness to make peace with another country. d. None of the above.

Bromine exists naturally as a mixture of bromine-79 and bromine-81 isotopes. An atom of bromine-79 contains: 34 protons and 35 electrons, only. 79 protons, 79 electrons, and 35 neutrons. 35 protons, 79 neutrons, and 35 electrons. 44 protons, 44 electrons, and 35 neutrons. 35 protons, 44 neutrons, 35 electrons.

A compound is found to contain 39.99 % carbon, 6.727 % hydrogen, and 53.28 % oxygen by mass What is the empirical formula for this compound?

Which of the following compounds is incorrectly named? CaO is calcium oxide MgSO3 is magnesium sulfite Mg(OH)₂ is magnesium dihydroxide NH4NO3 is ammonium nitrate K3PO4 is potassium phosphate

For the following reaction, 23.5 grams of iron are allowed to react with 5.58 grams of oxygen gas iron(s) + oxygen(g) → iron(II) oxide(s) A)What is the maximum mass of iron(II) oxide that can be formed? B)What is the FORMULA for the limiting reagent? C)What mass of the excess reagent remains after the reaction is complete?

The following reactions: Pb2+ + 21-→ Pbl2 2Ce4+ +21₂ + 2Ce³+ HAC + NH3 → NH4 + OẠC are examples of A)acid-base reactions. B)precipitation, acid-base, and redox reactions, respectively. C)redox, acid-base, and precipitation reactions, respectively. D)unbalanced reactions. E)precipitation, redox, and reactions, respectively.

Which of the following are transuranium elements? Choose all that apply. At Cf Bh Ba V

Paper clips are made of iron. If the average paper clip weighs 2 grams, how much does a mole of iron weigh? How many paper clips would be needed for a mole of iron?

Which of the following electron configurations is correct? Br: [Kr]4s²3d¹⁰4p⁷ Ca: [Ar]4s¹3d¹⁰ Mo: [Kr]5s²4d⁵ Ga: [Kr]4s²3d¹⁰4p¹ Br: [Xe]6s² 4f¹⁴5d¹⁰6p³

The moral that the story teaches us is a) Do not wear new clothing to parties b) Do not lie to others; you will be found out c) Do not aspire for more than you have; it will ruin you d) Do not wear expensive jewelry to parties

1. The element aluminum forms a_______ with the charge________ . 2. The symbol for this ion is _______ and the name is _________ ion. 3. The number of electrons in this ion is _______.

Dr. Raisa and her team of geologists have been studying GPS data that shows that two plates moved apart. Which diagram shows what happened between the two plates as they moved away from each other? (a) Diagram A: A new plate from underneath filled in the gap that was created by the plates moving apart. (b) Diagram B: Sand and dirt filled in the gap that was created by the plates moving apart. (c) Diagram C: Ocean water filled in the gap that was created by the plates moving apart. (d) Diagram D: Soft, solid rock from underneath the plates rose and hardened, adding solid rock to the edges both plates.

What is the valence electron configuration for the beryllium atom? What is the valence electron configuration for the nitrogen atom?

What is the name of the element with a valence electron configuration of 4s²4p³? What is the name of the element with a valence electron configuration of 3s²3p⁴?

Consider the following four cases i. A chemical process in which heat is absorbed. ii. A change in which q = 30 J, w = 44 J. iii A process in which a system does work on its surroundings with no change in q. iv. A process in which work is done on a system and an equal amount of heat is withdrawn. In how many of these cases does the internal energy of the system decrease? 0 1 2 3 4

What is Heisenberg's uncertainty principle? Electrons travel in discrete orbitals around the nucleus. It is impossible to know the exact position and speed of an electron at a given time. It is impossible to predict the spin of a moving electron. Electrons are negatively charged and nuclei are positively charged.

At a certain temperature, 0.4211 mol of N, and 1.541 mol of H, are placed in a 5.00 L container. N₂(g) + 3H₂ ⥨ 2NH3(g) At equilibrium, 0.1401 mol of N, is present. Calculate the equilibrium constant, Kc.

Which of the following correctly describes a sigma bond? a double bond a triple bond a bond formed when the nodes of two orbitals overlap a bond formed when two orbitals overlap end to end

XeFn+ mH2→ A(Contain Xe) + Other Products Regarding above reaction, which of the following option is correct : When n = 6 and m = 2, the hybridisation of Xe in A is sp^3d^2. When n = 2 and m = 1, then other products has a diatomic colored gas. When n = 6 and m = 3, then Electron pair structure of A is tetrahedral. When n = 6 and m = 1, the hybridisation of Xe in A is sp^3d.

A chemist mixes 22.6 g of ethanol with 7.47 g of acetone and 89.1 g of 1-bromobutane. Calculate the percent by mass of each component of this solution. Round each of your answers to 3 significant digits.

It is not considered safe to put a whipped cream container into a fire because the pressure will increase and cause an explosion. If a whipped cream container at 0.0 C is put into a campfire and its temperature is raised to 500. C, what was the initial pressure in the container if the final pressure is 29 atmospheres?

Which of the following describes the element F? (A) belongs to a group consisting entirely of gases (B) is one of the group of the least reactive elements (C) forms a basic solution in water (D) is very reactive as a metal (E) consists of diatomic molecules in elemental form (F) reacts vigorously with alkali metals to form salts

Which of the following describes the element Ba. a. forms a basic solution in water b. consists of diatomic molecules in elemental form c. is one of the group of the least reactive elements d. is found in nature only combined with other elements e. is very reactive as a metal f. reacts vigorously with alkali metals to form salts