CHEM100 FINAL

PV = nRT n = PV/RT V = nRT/P P = nRT/V P1V1 = P2V2 Ideal Gas at Standard Temperature and Pressure (STP) is at 0C/273.15K and 1 atm

R = 0.0821 Must convert to atm and kelvin

Which of the following is the net ionic equation for: CaBr2 (aq) + Na3PO4 (aq) → ... Make sure you create a balanced equation and use the solubility chart to determine solubility.

see picture

concentration units

solute/solution %w/w (m/m) = grams/grams %v/v = mL/mL %w/v (m/v) = grams or mg/mL Molarity (M) = mol/L

Going from a solid to a gas is known as _____.

sublimation

concentration and molarity are

synonymous

Complete the following table by filling in the blanks with either the correct number or the correct name. Element names should be capitalized and spelled correctly.

Name of Isotope

Which statement best describes the polarity of the OCl2 molecule?

OCl2 is polar because oxygen forms the 2- ion and chlorine forms the 1- ion OCl2 is nonpolar because the lone pairs and bonding pairs of electrons are equally distributed around the central atom OCl2 is polar because the O-Cl bonds are polar and not symmetrically distributed around the central atom OCl2 is nonpolar because the O-Cl bonds are nonpolar

(P1V1)/T1 = (P2V2)/T2 The initial state of a gas is P1= 3.50 atm, T1 = 45.0 ∘C and V1 = 0.900 L. The conditions were changed to V2= 8.50 L and T2 = 60.0 ∘C. What is the final pressure in atm?

P1= 3.5atm VI= .900L T1= 45 C P2= ? V2= 8.5 L T2= 60C P2 = P1V1T2/T1V2 P2= 3.5 x 0.900 L x 60*C / 45*C x 8.5 P2= 0.494

NET IONIC EQUATION of lead (II) nitrate and potassium chloride

Pb 2+ K+Cl- -----> PbCl_2 after balancing equation it becomes Pb 2+ (aq) + 2KCL- (aq) ----> PbCl_2

2 CO2 (g) + 4 H2O (l) ⇌ C2H8 (l) + 4 O2 (g) From the reaction above, what is the correct form of the equilibrium constant expression?

aA + bB ---> cC + dD Kc = [C]^c [D]^d -------------- [A]^a [B]^b ****cancel out any pure liquids**** like H2O or C2H8

solution concentration formula

amount of solute/amount of solution

net ionic equation

an ionic equation that includes only the particles that participate in the reaction; NO SPECTATORS

A sample of a pure aluminum halogen compound with a mass of 34.0 g contains 14.9 g of the aluminum. What is the percent composition of the aluminum in this compound? Enter your answer as a percent with the correct significant figures.

% composition = mass of element/total mass x 100 = 14.9/34.0 x 100 = 43.8%

What is the M of a 30% w/v (m/v) NaOH solution?

(m/v) = g/mL ---> solute/solution ---> 30g/100mL = 30% 1ml = .001L 100ml x .001L/1mL = 0.1 L 30g NaOH x 1mol NaOH/39.977g NaOH = .75mol/mL 0.75 mol/mL x 1ml/0.1L = 7.5 mol/L

Which of the following conversion factors are correct? Mark all that apply.

1 µg = 1 x 104 ng 1 L = 1 x 103 mL 1 kg = 1 x 103 g 1 cg = 1 x 10-2 g 1 Mg = 1 x 103 kg

Convert 0.0003140 g into µg. Select the correct answer with appropriate significant figures.

1. . 0.003140 m = 0.003140 x 1000000 μm = 314.0 μm 2. It is correct because there are 4 sig figs not 3. The zero after 314 counts as significant Answer = 314.0

Using the fictional units of zigs and zags (exact conversion 1 zig = 5.31 zags), determine how many zags are there in 68.91 zigs. Enter your answer with appropriate significant figures in standard notation.

1. 242 2. 1 zig = 5.31 zags ... If 1 zig is equal to over 5 zags then 68.91 zigs will be smaller than the amount of zags. So 5.31 x 68.91 = 241.8741. Correct sig figs = 242 zags

Which results in solution that 30% w/w (m/m) NaOH?

1. 30g NaOH and 100g H2O.... 30+100 = 130 30/130 = 23.08 2. 30g NaOH and 70g H2O... 30+70 = 100 30/100 = 30%

Identify the pairs of atoms that are isotopes:

1. not isotopes 2. not isotopes 3. isotopes *** ONLY SAME ELEMENT SYMBOL CAN HAVE ISOTOPES OF EACH OTHER***

Rules For Writing Formulas:

1. the cation is written first, followed by the monoatomic or polyatomic ion 2. the subscripts in the formula must be electrically neutral 3. subscripts are the smallest set of whole numbers 4. if only 1 poly atomic ion, don't use parentheses

Using the periodic table for this course, which substance contains the greatest number of atoms?

10.0 g Li 10.0 g Na 10 g Rb 10.0 g K ATOMS = MOLES X 6.023 10.0g Li / 6.94 = 1.441 x 6.022x10^23 10.0g Na / 22.99 = .4350 x 6.022x10^23 10.0g Rb / 85.47 = .1170 x 6.022x10^23 10.0g K / 39.10 = .2558 x 6.022x10^23 1. 8.50 (most) 2. 2.62 3. 7.05 4. 1.53 (least)

How many grams are there in 0.2350 mol of CaF2? The molar mass of CaF2 is 78.074 g/mol.

18.35 0.2350 mol CaF2 x 78.07g/1mol

A typical office has 335 ft2 of floor space. Calculate the floor space in m^2 and enter your answer with correct significant figures (3.28 ft = 1 m)

1m= 3.28 ft 1m x 1m = 3.28 ft x 3.28 ft 1m^2 = 10.75 ft^2 1ft^2 = 1/10.75 m^2 335ft^2 x 1/10.75 m^2 = 335/10.75 =31.16 sig figs 31.2.... canvas marked 31.1 correct

Add coefficients to balance the following equations (do not leave anything blank, add a "1" if necessary): ?C3H8O + ?O2 → ?CO2 + ?H2O ?BaCl2 + ?Na3PO4 → ?Ba3(PO4)2 + ?NaCl

2C3H8O + 9O2 ----> 6CO2 + 8H2O 3BaCl2 + 2 NaPO4 ---> 1 Ba3(PO4)2 + 6NaCl

A 9.41 g unknown gas sample occupied a 4.00 L container at 45.0 ∘C and 3.00 atm. Calculate its molar mass.

3.00atm x 4.00 L / 0.0821 x 318K = 4.60 mol Next we have the number of mole / mass / molar mass which looks like: 0.460mol = 9.41/ molar mass OR Molar Mass = 9.41/0.460 Molar Mass = 20.5 n = W/M W = mass of substance M = molar mass of substance M = 9.41g x 0.082 x 318.15 K -------------------------------- 3.00 atm x 4.00 L M= 20.4 g/mol

How many oxygen atoms are present in 4.0 mol Ca(OH)2?

4.8 X 10^24

How many moles of Al2(SO4)3 can be produced from 55.5 g of H2SO4?

55.5g of H2SO4 --> mol of Al(OH)3 3 moles of H2SO4 gives 1 mole of Al2(SO4)3 55.5g x 1 mol/98.079g x 1/3 = 0.264

An isotope of an ion has a mass number of 38 and has 18 electrons. Which symbol could be the isotope?

56Sr2+ 38Cl- 38K 56Ar 38S-

Which of the following numbers are correctly expressed in decimal form? Mark all that apply.

6.21 x 105 = 621,000 9.03 x 10—4 = 0.000903 7.28 x 106 = 0.00000728 1.12 x 10—3 = 1,120

How many grams of H2O can be produced from 79.0 g Al(OH)3?

79.0g Al(OH)3 x 1 molAl(OH)3 /88.003g Al(OH)3 x 6mol H2O / 2 mol Al(OH)3 x 32.0 gram O2 / 1 mol H2o

In which situation would molecules in a sample of a substance exhibit hydrogen bonding intermolecular forces?

A molecule with hydrogen atoms bonded to nitrogen atoms will exhibit hydrogen bonding intermolecular forces with other identical molecules.

The cations and anions Al3+ and CO32- Ca2+ and CrO42- Na+ and So32- make what compound formula

Al2(CO3)3 CaCrO4 Na2SO3

Identify the true statement about atomic spectra.

All atomic spectra contain all colors of visible light because electrons can emit any color of light when they move between energy levels. The colored lines in atomic spectra are unique to each element because each element has a different number of neutrons. All atomic spectra contain all colors of visible light, indicating that all atoms contain electrons. The colored lines in atomic spectra are a result of specific energy levels electrons can move between.

Which neutral atom or ion would have the electron configuration 1s22s22p63s23p6 ? Select Yes if the configuration for the neutral atom or ion could be 1s22s22p63s23p6 Select No if it the configuration for the neutral atom or ion could not be 1s22s22p63s23p6

Ar : Yes S2+ : No Cl- : Yes K- : No Al3- : No

Identify the true statement about carbonic acid, H2CO3.

Carbonic acid is amphoteric. Carbonic acid is a strong acid. The carbonate ion is a weak acid. Carbonic acid is a diprotic acid. The carbonate ion is a strong base.

The carbonate ion, CO_3^2-, is a resonance structure, why?

Because there is a lone pair on the central atom. The double bond can be drawn between the carbon and any of the oxygens. There are only single bonds in the entire structure. The double bond must be drawn between the carbon and the left-most oxygen

Consider a sample of 1.0 mole of Cl2 molecules and 1.0 mole of Sr atoms. Identify if each statement is true or false.

Both samples contain the same number of atoms FALSE Both samples have the same mass in grams FALSE Both samples contain 6.022 x 1023 atoms FALSE Both samples contain 6.022 x 1023 particles (molecules or atoms) TRUE The sample of 1.0 mole of Cl2 weighs more than the sample of 1.0 mole of Sr FALSE

Which of the following atoms or molecules will have the strongest London dispersion forces with other identical molecules?

C3H6 N2 He C6H14 F2

Identify the reducing agent in this reaction: C4H12 + 7 O2 → 4 CO2 + 6 H2O

C4H12 is the correct answer. Reducing agents are those species that get oxidized in the reaction. ***find individual oxidation numbers*** The oxidation number of C in C4H12 is -4 whereas oxidation number of C in CO2 is +4 this means C is oxidized in this reaction therefore C4H12 is a reducing agent.

Which of the following molecules when mixed together will form a solution?

CCl4 and C2H5OH - does not CHF3 and NH3 - does C4H10 and CH3OH - does not C8H18 and C3H7 - does H2O and C6H14 - does not

Draw each Lewis structure and use it to complete the following table with a yes or no answer to the question, "Does this secondary (intermolecular) force operate between the molecules of the given compound?"

CF4 : 1. london dispersion force 2. no dipole dipole 3. no hydrogen bond CHCl3 : 1. london dispersion 2. dipole-diople 3.no hydrogen bond NH3 : 1. london dispersion 2. dipole-diople 3. hydrogen bond

sodium acetate aluminum nitrate magnesium carbonate

CH3COONa Al(NO3)3 MgCO3

Samples of matter may be classified in several ways: as pure substance or mixture; for mixtures, homogeneous or heterogeneous; and, for pure substances, element or compound. CO2 - carbon dioxide Sugar Water

CO2- pure, neither homogeneous or heterogeneous, a compound Sugar Water - mixture, homogeneous, and neither an element or compound

calcium perchlorate

Ca(ClO4)2

The decomposition of ozone can be described by the following two-step reaction sequence: Step 1: Cl + O3 → ClO + O2 Step 2: ClO + O → Cl + O2 Which species is a catalyst in this mechanism?

Cl

For each chemical name, decide if it is ionic, covalent, or an acid:

Cobalt (III) Chloride: Metal (Co) + Nonmetal Cl : ionic Ammonia: NH3 Nonmetal (N) + Nonmetal (H) : covalent Sulfur Hexafluoride: SFl6 Nonmetal (S) + Nonmetal (Fl) : covalent Acetic Acid: Acid is in the name / easy give away CORRECTION: Ammonium Sulfite: NH3SO3 Formed from two polyatomic ions thus creates an ionic compound.

chromium (II) iodide chromium (III) chloride cobalt (II) bromide copper (II) oxide

CrI2 CrCl3 CoBr2 CuO

For each chemical formula, decide if it should be named using ionic, covalent, or acid naming rules:

CuO - ionic H3PO4 - acid PCl5 - covalent CaCl2 - ionic NH4NO2 - ionic

Which statement best explains what is occurring during a phase change from solid to liquid?

During a phase change the temperature stays constant as heat energy is added because the energy is used to disrupt intermolecular forces and allow molecules to move faster. During a phase change the temperature increases because the molecules are breaking down into their individual protons, neutrons, and electrons. During a phase change the temperature increases because the molecules are getting hotter. During a phase change the temperature increases because the molecules are moving faster. During a phase change the temperature stays constant as heat energy is added because a chemical reaction is occurring and the energy is used to break bonds and free individual atoms.

Match the answer to the appropriate letter in the diagram of Beryllium-9.

F is 4 not 9

Evaporation and boiling are identical processes

FALSE

Vaporization describes the transition from gas to liquid

FALSE

Calculate the mass, in mg, of 450.0 mL rubbing alcohol, which has a density of 0.7860 g/mL. Your answer should be in scientific notation with proper significant figures and units.

Given: Volume = 450.0 mL Density = 0.7860 g/mL Calculating: mass in mg Density = mass/volume Mass = density x volume M = 0.786 g/mL x 450mL = 353.7 4 sig figs..... 3.537 x 10^5 mg

If a new element was discovered that was found to form ions by gaining one electron, which group on the periodic table does this element belong with?

Group 5 Group 8 Group 2 Group 1 Group 3 Group 6 Group 7

Use the acid naming rules discussed in class to predict the formula for carbonous acid.

H2CO2 I think originally I must have forgotten that acids begin with an H (hydrogen) and focused too much on the conversion. I know that -ous comes from -ite which translates to CO3 (2-) BUT -ate suffixes have 1 more Oxygen than -ite suffixes. So it's actually CO2(2-). Now knowing that I must've rushed through and forgot to add in the Hydrogens to make it an acid I know the correct answer is H2CO2

Given the following balanced equation indicate on the reactant side if the compound is an acid or base and on the product side if the compound is the conjugate acid (Conj. Acid) and conjugate base (Conj. Base): H2PO4- (aq) + H2O (l) ⇌ HPO42- (aq) + H3O+ (aq)

H2PO4- (aq) : acid H2O (l): base HPO42- (aq) : conj. base H3O+ (aq): conj. acid

For each of the following chemical compounds are the name and formula matched correctly or incorrectly?

HCl : Chlorous Acid (incorrect) Nitrate : NO2- (incorrect) PCl5 : Phosphorus Pentachloride (correct) Calcium (II) Oxide : CaO (incorrect) AgCl : Silver Chloride (correct) Iron (III) Oxide : Ir2O3 (incorrect)

Use the following information to complete the table. Balanced equation: 2 Al(OH)3 + 3 H2SO4 → Al2(SO4)3 + 6 H2O

How many moles of Al(OH)3 will react with 0.45 mol of H2SO4? moles of Al(OH)3 / 2 = moles of H2SO4 / 3 moles of Al(OH)3 = 2/3 x .45 = 0.30

Using the rules learned in class, draw the Lewis structure of SeO2 and use it to answer the following questions. Enter your answers as whole numbers, not words.

How many valence electrons were used to make the drawing: 18 How many lone pairs of electrons are around the central atom: 1 How many bonding pairs of electrons are around the central atom: 4 (not 2)... 2 sigma and 2 pi bonds What is the molecular geometry (shape)? bent

Given the following equilibrium reaction, identify the effect each change will have as the reaction shifts to reestablish equilibrium. C (s) + O2 (g) ⇌ CO2 (g) ΔH = -256 kJ Decide if each change would cause the reaction to shift to favor reactants, products, or cause no change.

Increase in the temperature: favor reactants Increase in concentration of C: favor products Decrease in reactants: favor reactants Add a catalyst: no effect/change on equilibrium

Identify the chemical property:

Iron melts at 1535 ºC Carbon dioxide dissolves in water When heated with oxygen, magnesium changes from a shiny metal to a white solid that no longer conducts electricity Water boils at 100ºC

Calculate the osmolarity of K2SO4 and glucose if the concentrations were 0.5 M and 0.8 respectively.

K2SO4 = K+ K+ SO4- K2SO4 (i) = 3 K2SO4 --------> 0.5 x 3 = 1.5 M C6H12O6 (i) = 1 C6H12O6 --------> 0.8 x 1 = 0.8 M 0.8 M + 1.5 M = 2.3 osmol/L

Fill in the table with the proper oxidation number for each atom of Li3PO4:

L : +1 P: +5 O: +2

Identify the weakest and strongest acids.

Larger the value of ka more will be stronger acid. Oxalic acid has highest ka so it will be strongest acid. Acetic acid has lowest ka so it will be weakest acid.

How much water should you ADD to make 1.0 M solution from 325 mL of a 3.0 M solution?

M1V1=M2V2 M1 = 1.0 M V1 = ? M2 = 3.0 M V2 = 325 mL (1.0M)V1 = (3.0M)(325mL) V1 = 975 mL ****** How much should you ADD*** 975mL (end) - 375 (beginning) ------------------------ = 650 mL of H2O

You prepared 750mL of a 0.50M solution by adding water to 137 mL of a concentrated solution. What was the molarity of the original/initial solution?

M1V1=M2V2 M1 = ? V1 = 137 mL or 0.137 L M2 = 0.50 M V2 = 750 mL or 0.750 L M1(.137) = (0.50M)(.750L) M1 = 2.7 M

If 10.0 g of Cu2SO4 is dissolved in enough water to give 250 mL of solution what is the molarity of Cu2SO4?

M=mol/L Cu2SO4 = 22.15g/mol 250mL = 0.250L 10g x 1mol/223.15g = 0.0448mol Cu2SO4 M = 0.0448mol/.250L M = 0.179

What is the concentration of a solution made from dissolving 3.0 mol of NaCl in H2O to make 1.5L of solution

M=mol/L M= 3.0mol/1.5L =2.0 *if mmol ---> .003 mol *if 1.5mL ---> .0015 L

By chemical analysis, the composition of an unknown compound was found to be 43.64% phosphorus and 56.36% oxygen. Its molecular mass was shown to be 426 g/mol. Determine its molecular formula using provided molar masses of each element: P = 30.974 g/mol O = 15.999 g/mol

Molecular Formula: P6O15 P 43.64/30.974 = 1.409/1.409 = 1 O = 56.3/15.999= 3.52/1.409= 2.5 ***cannot have half numbers so DOUBLE***** P: 1x2 = 2 O: 2.5 x 2 = 5 P2O5 = 141.943 GIVEN: 426 g/mol / 141.943 = 3.00 3(P2O5) = P6O15

Identify the correct statement using the given Lewis structures

Substance A will have a higher melting point because its molecules experience hydrogen bonding forces while Substance B molecules only experience dipole-dipole and London dispersion forces

What is the temperature, in °C, of a sample of 0.165 mol of gas at 1.830 atm in a volume of 5.00 L?

T = PV/nR T = (183)(5)/(0.165)(0.0821) T = 675.78 - 273.15 T= 403

Boiling can occur without adding heat to a liquid

TRUE

Boiling occurs when vapor pressure is the same as atmospheric pressure

TRUE

Iron has three common stable isotopes, 54Fe, 56Fe, and 57Fe; given the average atomic mass on the periodic table, which statement is true.

The 56Fe isotope must be more abundant because the average atomic mass is closest to 56 amu. All three isotopes must be equally abundant because the average atomic mass does not perfectly match any of the three isotopes. The 57Fe isotope must be more abundant because it is the largest and most stable. The 54Fe isotope must be more abundant because it is the smallest and most stable. The 54Fe isotope must be more abundant because the average atomic mass is smaller than 56 amu.

Imagine a new temperature scale, called the Aztec, is created where water freezes at 50 °A and boils at 150 °A. If you wanted to convert between Celsius and Aztec units, which statement is most correct.

The conversion would involve adding a negative sign to the Aztec value to convert it to Celsius The conversion would involve multiplying by a constant since the degree sizes are different on the two scales The conversion would involve adding a constant since the freezing points are different on the two scales The conversion would involve both multiplying by a constant and adding a constant since the degree sizes and freezing points are different on the two scales - Basically the Aztec temperature scale from 50 degrees A to 100 degrees A is a 100 degree difference. When using real units and temperature scales such as Celsius the standard freezing point is 0 degrees and boiling point is 100 degrees. The difference is the same between the fake units and real units so you'd only add a constant to the equation

Select the true statement:

The formulas for elements and compounds can be written using symbols on the periodic table Mixtures are types of pure substances Homogeneous mixtures can only be separated by chemical changes The properties of compounds are a mixture of the properties of the elements that formed them

Select either true or false for each of the following statements describing individual molecules of matter in the gaseous state:

The gas molecules travel in straight lines through space until they bounce off of something. TRUE The gas molecules exhibit strong attractive forces between one another. FALSE The gas molecules exert pressure upon the walls of whatever container in which they are placed. TRUE The gas molecules spread out to fill whatever size or shape of the container in which they are placed. TRUE The structure of individual molecules in their gaseous state remains unchanged as they change to their liquid or solid states. TRUE

Which statement is true about a reaction at equilibrium?

The ratio of the reactants to products is always less than 1. The rate of the forward reaction is equal to the rate of the reverse (back) reaction. The concentration of the reactants is equal to the concentration of the products The reaction stops and products and reactants are no longer produced or consumed. All of these statements are true about a reaction at equilibrium

Read each statement concerning the graph below and select the letter that best matches the statement.

The segment where molecules in the solid state are increasing in temperature (A) The segment where molecules in the liquid and gas state coexist (D) The segment where a phase change from solid to liquid is occurring (B) The segment where molecules have the least kinetic energy (A) Identify the boiling point temperature (80 degrees)

Initially, 8.00 moles of a gas occupies 0.300 L. The number of moles changed to 3.50 moles. What is the final volume, in L, of the gas?

V = 0.131 L V1/n1 = V2/n2 n1= 8.00 mol V1 = 0.300L n2= 3.50 mol V2 = ? 0.3/8 = v2/3.5 v2 = (3.5)(0.3/8) V = 0.131 L

A substance with strong intermolecular forces will have a relatively low ______.

Vapor pressure

Going from a gas to a liquid is known as _____.

condensation

If the Kelvin temperature of gas is doubled at constant volume and moles, the pressure:

decreases by a factor of four. remains the same. increases by a factor of four. decreases by a factor of two. increases by a factor of two.

Which statement best describes what is happening in a redox reaction?

electrons are being lost during oxidation and gained during reduction

Moles of reactants must be the same as the total moles of products The total mass of reactants must be the same as the total mass of the products The sum of the coefficient of the products must equal the sum of the coefficients The subscripts tell the number of grams of each substance present The coefficients tell the number of moles of each substance present The total number of atoms of reactants must be the same as the total number of atoms of products

false true false false true true

Calculate the pH of an aqueous solution consisting of 0.070 M Li2HPO4 and 0.085 M Li3PO4. The Ka for HPO42- is 4.84 x 10-13.

given... 0.070 M of Li2HPO4 (acid) 0.085 M of Li3PO4 (conj base) Ka of HPO4 = 4.84 x 10^-13 pH = -log(4.84E13) + log (0.85M/0.70M) pH = 12.315 + 0.8432 = 12.4

How many grams of MgCl2 are contained in 35.0 mL of a 0.490 M solution? Molar Mass of MgCl2 = 95.211 g/mol

molarity = weight of solue / molar weight x 1 / V M = 0.490 V = 35.0 ml or 0.035 L 0.490 = w/ 95.211 x 1/ 0.35 W = .490 mol/L x 95.211 x .035 = 1.63

Volume =

moles / concentration (M)

If 5.22 liters of H2(g) gas at 113 °C and 0.680 atm is used, what volume of HF(g) gas will be formed if it is collected at 72 °C and 0.430 atm?

n = PV/RT then V=nRT/P R = 0.0821

LiCl Ba(CN)2 CaF2

neutral basic basic

Which of the following aqueous solutions would result in the greatest osmotic pressure if it were separated from pure water by a semi-permeable membrane? In other words, which of the following solutions exhibits the highest "osmolarity"? 0.3 M NaF 0.3 M Na2CO3 0.3 M C6H12O6 0.3 M (NH4)3PO4 0.3 M Ca(NO3)2

osmotic pressure = icRT i = vant hoff factor c = concepntration R = universal gas constant t = temp vant hoff factor = observed/ theoretical ****C6H12O6 = 1 because it does not dissociate**** NaF dissociates to form: 1 Na+ and 1 F- ion = 2 Na2CO3: Na2 + and CO3 2- = 3 ****C6H12O6 = 1 because it does not dissociate**** continue down and (NH4)3PO4 is the correct answer with 4

Which subatomic particle is the only one that can be used to uniquely identify an element?

proton nucleus electron neturon

Which solids will have the lowest melting point?

they are all about the same metallic molecular ionic

A gas cylinder of volume 22.4 liters holds a mixture of neon, oxygen, and nitrogen gases at standard temperature and pressure (0°C and 1 atm). If there are 0.3 moles of oxygen and 0.5 moles of nitrogen, then how many moles of neon are in the container?

v = 22.4 l t = 0C P = 1 atm n = 0.3 (O2) and 0.5 (N2) 1 - (0.5+0.3) 1- 0.8 = 0.2

What volume of a 0.500M HNO3 solution contains 6.00mol of HNO3?

volume = mL or L 6.00mol HNO3 x 1 Liter/0.500 mol = 12.0 L

What is the molarity of a 20.0% w/v (m/v) KCl solution? The information below may be helpful: Molar mass of KCl: 74.551 g/mol Density of water: 1 g/mL

w/v = weight of KCl / volume of solution 20.0/100 ml x 100 = 20% weight of KCl = 20 Volume = 100ml = 0.1 L Molarity = mass/ molar mass --------------------- 0.1 M = 20 x 74.55 / 0.1 M = 2.68

What was the molar concentration of 50.0 mL of an aqueous H2SO4 solution that required 77.5 mL of a 0.0520 M standard solution of LiOH for complete neutralization?

write balanced eq: H2SO4 + 2LiOH --> Li2SO4 + 2H2O M1V1= M2V2 M1 (50ml) = 0.0520M x 77.5mL M1 = 0.0807