CHEM FINAL REVIEW QUESTIONS

Perform each calculation with the correct number of significant figures. (a) 1.10x0.5120x4.0015/3.4555 (b) 0.355+105.1-100.5830 (c) 4.562x3.99870/(452.6755-452.33) (d) (14.84x0.55)-8.02

(a) 0.652 (b) 4.9 (c) 53 (d) 0.1

Write electron configuration for each element. (a) Mg (b) P (c) Br (d) Al

(a) 1s²2s²2p⁶3s² (b) 1s²2s2p⁶3s²3p⁶ (c) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁵ (d) 1s²2s²2p⁶3s²3p¹

Write complete ionic and net ionic equations for the reaction. (a) 3SrCl₂(aq) + 2Li₃PO₄(aq) --> Sr₃(PO₄)₂(s) + 6LiCl(aq)

(a) 3Sr²⁺(aq) + 6Cl⁻(aq) + 6Li⁺(aq) + 2PO₄³⁻(aq) --> Sr₃(PO₄)₂(s) + 6Li⁺(aq) +6Cl⁻(aq) 3Sr²⁺(aq) + 2PO₄³⁻(aq) --> Sr₃(PO₄)₂(s)

On the basis of periodic trends,choose the larger atom in each pair. (a) C or F (b) C or Ge (c) N or Al (d) Al or Ge

(a) C (b) Ge (c) Al (d) indeterminate

Write empirical formulas for the compounds represented by the molecular formulas. (a) C₄H₈ (b) B₂H₆ (c)CCl₄

(a) CH₂ (b) BH₃ (c) CCl₄

On the basis of periodic trends,choose the atom in each pair that has the highest first ionization energy. (a) Al or S (b) As or Sb (c) N or Si (d) O or Cl

(a) S (b) As (c) N (d) indeterminate

On the basis of periodic trends,choose the more metallic element from each pair. (a) Sn or Te (b) P or Sb (c) Ge or In (d) S or Br

(a) Sn (b) Sb (c) In (d) indeterminate

Classify each of the substances as an atomic element, molecular element, molecular compound, or ionic compound. (a) xenon (b) NiCl₂ (c) bromine (d) NO₂ (e) NaNO₃

(a) atomic element (b) ionic compound (c) molecular element (d) molecular compound (e) ionic compound

Classify each crystalline solid as molecular, ionic, or atomic. (a) Au(s) (b) CH₃CH₂OH(s) (c) CaF₂(s)

(a) atomic solid (b) molecular solid (c) ionic solid

How many significant figures are in each number? (a) 0.04450m (b) 5.0003km (c) 10dm=1m (d) 1.000x10⁵s (e) 0.00002mm (f) 10,000m

(a) four (b) five (c) unlimited-defined quantities have an unlimited amount of sig figs (d) one (e) ambiguous- trailing zeros occur before an implied decimal point and therefore are ambiguous. Assume 1 sig fig unless given more information.

Which substance has the highest boiling point? (a) CH₂OH (b) CO (c) N₂

(a) hydrogen bonding

Which element would you dope into germanium to create a p-type semiconductor? (a) indium (b) tin (c) arsenic

(a) indium has three valence electrons and germanium has four, the presence of indium would introduce holes into the valence band, resulting in a p-type semiconductor.

Predict whether each compound is soluble or insoluble (a) PbCl₂ (b) CuCl₂ (c) Ca(NO₃)₂ (d) BaSO₄

(a) insoluble (b) soluble (c) soluble (d) insoluble

Classify the bonds formed between each pair of electrons as covalent, polar covalent, or ionic. (a) Sr and F (b) N and Cl (c) N and O

(a) ionic (b) covalent (c) polar covalent

Name the oxyacid (a)HNO₃ (b)H₂SO₃

(a) nitric acid because it is ends in -ate (b) sulfurous acid because it ends in -ite

Name each compound: (a) NI₃ (b) PCl₅ (c) P₄s₁₀

(a) nitrogen triiodide (b) phosphorus pentachloride (c) tetraphosphorus decasulfide

Which molecules have dipole-dipole forces? (a) CO₂ (b) CH₂Cl₂ (c) CH₄

(a) no, the bonds are polar bonds, and geometry is linear (b) yes, (C-Cl) is polar, and (C-H) is nonpolar geometry is nonpolar (c) no, (C-H) nonpolar, geometry tetrahedral(may cancel out slight bond polarities)

Determine whether each change is physical or chemical. (a) the evaporation of rubbing alcohol (b) the burning of lamp oil (c) the bleaching of hair with hydrogen peroxide (d) the formation of frost on a cold night

(a) physical (b) chemical (c) chemical (d) physical

Determine whether each change is physical or chemical. (a) A copper wire is hammered flat (b) A nickel dissolves in acid to form a blue-green solution (c) Dry ice sublimes without melting (d) A match ignites when struck on a flint

(a) physical (b) chemical (c) physical (d) chemical

Determine whether the following reactions are redox . (a) 2Mg(s) + O₂(g) --> 2MgO(s) (b) 2HBr(aq) + Ca(OH)₂(aq) --> 2H₂O(l) + CaBr₂(aq) (c) Zn(s) + Fe²⁺ (aq) --> Zn²⁺(aq) + Fe(s)

(a) yes because magnesium increases in oxidation number and oxygen decreases. (b) no. none of the atoms go through a change in oxidation number (c)yes because zinc increases in oxidation number while iron decreases.

Which statement is true? (a) For a given element, the size of an isotope with more neutrons is larger than one with fewer neutrons. (b) For a given element, the size of an atom is the same for all of the element's isotopes.

(b) The number of neutrons in the nucleus of an atom does not affect the atom's size because the nucleus is miniscule compared to the atom itself.

Which molecule could have an expanded octet? (a) H₂CO₃ (b) H₃PO₄ (c) HNO₂

(b) because phosphorus isa third-period element. Expanded octets never occur in second-period elements like carbon and nitrogen.

A substance has a triple point at -24.5°C and 225 mmHg. What is most likely to happen to a solid sample of the substances as it is warmed from -35°C to 0°C at a pressure of 220 mmHg? (a) The solid melts into a liquid (b) The solid sublimes into a gas (c) Nothing

(b) the the pressure is below the triple point

The density of copper decreases as temperature increases. Which change occurs in a sample of copper when it is warmed from room temperature to 95°C? (a) The sample becomes lighted (b) The sample becomes heavier (c) The sample expands (d) The sample contracts

(c) The copper sample expands. However because its mass remains constant while its volume increases, its density decreases.

Which halogen has the highest boiling point? (a) Cl₂ (B) Br₂ (c) I₂

(c) it has the highest molar mass

Which molecule would you expect to be a free radical? (a) CO (b) CO₂ (c) N₂O (d) NO₂

(d) because the sum of the valence electrons is an odd number

A sample of gas has a volume of 2.80 L at an unknown temperature. When the sample is submerged in ice water at T= 0.00°C, its volume decreases to 2.57 L. What is the initial temperature in K and in °C?

0.00+273.15= 273.15 K 2.80(273.15)/2.57 297.6K and 24°C

Calculate the amount of carbon (in moles) contained in a 0.0265 g pencil "lead."

0.0265 / 12.01= 2.21(10⁻³)

How many liters of a 0.125 M Na OH solution contain 0.255 mol of NaOH?

0.125M(0.125 mol)= 2.04L

What volume of 0.150 M KCl solution will completely react with 0.150 L of a 0.175 M Pb(NO₃)₂ solution according to the following balanced equation? 2KCl(aq)+ Pb(NO₃)₂(aq) ---> PbCl₂(s)+ 2KNO₃(aq)

0.150 L Pb( 0.175 mol)(2mol K)/0.150mol K) 0.350 L KCl solution

Calculate the volume occupied by 0.845mol of nitrogen at a pressure of 1.37 atm and a temperature of 315 K.

0.845(0.08206)(315)/1.37 15.9L

A high performance road bicycle tire is inflated to a total pressure of 132 psi. What is this pressure in mmHg?

1 atm=14.7 psi 760mmHg=1 atm 132(1)(760)/14.7(1) 6.82(10³)mmHg

What mass of hydrogen (in grams) in contained in 1.00 gallon of water? The density of water is 1.00 g/mL.

1.00gal H₂O x _3.785L_ x _1000mL_ x 1.00g 1 gal 1L mL 3.785(10³)g H₂O 3.785(10³) x _1 molH₂O_ x _2mol H_ x _1.008g H 18.02 g H₂O 1mol H₂O 1mol H 4.23(10²)g H

How many grams of water form when 1.24 L of H₂ gas at STP completely reacts with O₂?

1.24(1)(2)(18.02)/(22.4(2(1))) 0.998g

A metal cube has an edge that is 11.4mm long and a mass of 6.67g. Calculate the density of the metal.

11.4mm =>1.14cm (1.14cm)³=> 1.48154cm³ 6.67/1.48154= 4.502g/cm³

The titration of 10.00 mL of HCl solution of unknown concentration requires 12.54 mL of a 0.100 M NaOH solution to reach the equivalence point. What is the concentration of the unknown HCl solution in M?

12.54(1)(0.100)(1)/(1000)(1)(1)= 1.23(10⁻³) 1.23(10⁻³)/0.0100= 0.125 M HCl

Calculate the density of nitrogen at 125°C and a pressure of 755 mmHg,

125+273= 398 K 755/760=0.99342 atm 0.99342(28.02)/0.08206(398)) 0.852g/L

An LP gas tank in a home barbeque contains 13.2 kg of propane, C₃H₈. Calculate the heat kJ associated with the complete combustion of all ³thepropane ³n the tank. C₃H₈(g)+ 5O₂(g) --> 3CO₂(g) +4H₂O(g) AHrxn= -2044kJ

13.2(1000)(1)(-2044)/(1(22.09(1))) -6.12(10⁵) kJ

When an X-ray beam of wavelength=154 pm is incident on the surface of an iron crystal, it produces a maximum diffraction at an angle of x=32.6°. Assuming n=1, calculate the separate between layers or iron atoms in the crystal.

154/2sin(32.6) 143pm

Calculate the mass of water in grams that can be vaporized at its boiling point with 155 kJ of heat.

155kJ(1mol)(18.02)/(40.7kJ(1mol))= 68.6 g H₂O

To what volume should you dilute 0.200 L of a 15.0 M NaOH solution to obtain a 3.00 M NaOH solution?

15m/L(0.200L)/3mol/L 1.00L

The empirical formula for butanedione is C₂H₃O,and its molar mass is 86.09 g/mol. Determine its molecular formula.

2(12.01 g/mol) + 3(1.008 g/mol) + 16.00 g/mol= 43.04 g/mol 86.09/43.04= 2 C₂H₃O x 2 = C₄H₆O₂

How many sp hybrid orbitals result from the hybridization of s and p orbitals?

2. Sum the superscripts of the hybridization notation

Upon combustion, a 0.8233-g sample of a compound containing only carbon, hydrogen, and oxygen produces 2.445 g CO₂ and 0.6003 g H₂O. Find the empirical formula of the compound.

2.445g/44.01 g CO₂= 0.05556 mol CO₂ 0.6003/18.02 g H₂O= 0.03331 mol H₂O 0.05556 mol CO₂= 0.05556 mol C 0.03331 mol H₂O x 2= 0.06662 mol H 0.05556(12.02)= 0.6673g C 0.06662(1.008)= 0.06715g H O= 0.8233-(0.6673+0.06715)= 0.0889g mol O= 0.0889g O/16.00 O= 0.00556 mol C₁₀H₁₂O

Calculate the number of copper atoms in 2.45 mol of copper.

2.45 x 6.022(10²³)= 1.48(10²⁴) Cu atoms

The U.S. Food and Drug Administration recommends that an adult consume less than 2.4 g of sodium per day. What mass of sodium chloride (in grams) can you consume and still be within FDA guideline? Sodium chloride is 39% sodium by mass.

2.4g Na x _100g NaCl_ 39g Na 6.2 g NaCl

A male athlete in a kinesiology research study has a lung volume of 6.15 L during a deep inhalation.At this volume, his lungs contain 0.254 mol of air. During exhalation, his lung volume decreases to 2.55L. How many moles of gas did the athlete exhale? Assume constant temperature and pressure.

2.55(0.254)/6.15 0.105mol 0.254-0.105= 0.149mol

Find AHrxn for the reaction: 3C(s)+4H₂(g)-->C₃H₈(g) Use the reactions with known AH's C₃H₈(g)+5O₂(g)-->3CO₂(g)+4H₂O(g) AH= -2043 kJ C(s)+O₂(g)-->CO₂(g) AH= -393.5 kJ 2H₂(g)+O₂(g)-->2H₂O(g) AH= -483.6 kJ

2043-1181-967.2 -105kJ

Calculate the number of moles of gas in a 3.24-L basketball inflated to a total pressure of 24.3 psi at 25°C.

24.3/14.7= 1.6531 atm 25+273.= 298K 1.6531(3.24)/(0.08206(298)) 0.219 mol

A compound containing nitrogen and oxygen is decomposed in the laboratory. It produces 24.5 g nitrogen and 70.0 g oxygen. Calculate the empirical formula of the compound.

24.5 g N x _1mol N_ 14.01g N 1.74mol N 70.0 g O x _1mol O_ 16.00 g O 4.38 mol O 1.74/1.74 =1 4.38/1.74 =2.5 1(2)= 2 2.5(2) = 5 N₂O₅

An unknown gas effuses at a rate that is 0.462 times that of nitrogen gas. Calculate the molar mass of the unknown gas in g/mol.

28.02/(0.462)²= 131 g/mol

Calculate the root mean square velocity of oxygen molecules at 25°C.

298 K M=32(1)/1(1000)= 32(10⁻³) sqrt(3(8.314(298))/32(10⁻³)) sqrt(2.32(10⁵) 482m/s

Write complete ionic and net ionic equations for the reaction. (a) HI(aq) +Ba(OH)₂(aq) --> H₂O(l) + BaI₂(aq)

2HI(aq) +Ba(OH)₂(aq) --> 2H₂O(l) + BaI₂(aq) 2H⁺(aq) +2OH⁻(aq) --> 2H₂O(l)

How many copper atoms are in a copper penny with a mass of 3.10g?

3.10 g x _1 mol C_ x _6.022(10²³)_ = 63.55g Cu 1 mol Cu 2.94(10²²) Cu atoms

a 32.5 g cube of aluminum initially at 45.8°C is submerged into 105.3 g of water at 15.4°C. What is the final temperature of both substances at thermal equilibrium? AT = delta T Tf = temperature final pg 262

32.5g(0.903J)(AT Al)=105.3g(4.18J)(AT H₂O) (AT Al)=-14.998(AT H₂O) Tf-Ti, Al=-14.998(Tf-Ti, H₂O) 14.998(15.4)+24.8/(15.998) 17.3°C

An aspirin tablet contains 325 mg of acetylsalicylic acid (C₉H₈O₄). How many acetylsalicylic acid molecules does it contain?

325mg x _10⁻³g_ x _1mol_ x _6.022(10²³) 1mg 180.16 1 mol 1.09(10²¹)

A nitrogen gas laser pulse with a wavelength of 337 nm contains 3.83 mJ of energy. How many photons does it contain?

337nm(10⁻⁹)= 3.37(10⁻⁷) 6.626(10⁻³⁴⁴)(3(10⁸))/3.37(10⁻⁷)) 5.8985(10⁻¹⁹)J 3.83(10⁻³)/5.8985(10⁻¹⁹)J 6.49(10¹⁵)

What volume of hydrogen gas, at temperature of 355 K and a pressure of 738 mmHg, is needed to synthesize 35.7 g of methanol?

35.7/32.04= 1.1142 mol 1.1142(2)=2.2284 mol 738/760 = 0.97105 2.2284(0.08206)(355).0.97105 66.9 L

Suppose that a plant consumes 37.8 g of CO₂ in one week. Assuming that there is more than enough water present to react with all of the CO₂, what mass of glucoseC₂H₆O₂ can the plant synthesize from the CO₂?

37.8g x _1 mol_ x_1mol_x_180.2g_ 44.01 g 6 mol 1mol 25.8 g

Calculate the mass percent of Cl in Freon-112 (C₂Cl₄F₂).

4(35.45)= 141.8g/mol Cl 2(12.02) + 4(35.45) +2(19.00) mmC₂Cl₄F₂ 141.8/203.8 x 100% 69.58%

How many sp³ hybrid orbitals result from the hybridization of s and p orbitals?

4. Sum the superscripts of the hybridization notation

Calculate the packing efficiency of a simple cubic unit cell.

4/24(pi)(100%)= 52.36%

Calculate the formula mass of C₆H₁₂O₆.

6(12.01 amu) + 12(1.008 amu) + 6(16.00 amu) 180.16 amu

Calculate the wavelength of an electron traveling with a speed of 2.65(10⁶)m/s mass of an electron: 9.11(10⁻¹⁰)

6.626(⁻³⁴)/(9.11(10⁻¹⁰)(2.65(10⁶)) 2.74(10⁻¹⁰)

A 1.00-L mixture of helium, neon, and argon has a total pressure of 662 mmHg at 298 K.If the partial pressure of helium is 341 mmHg and the partial pressure of neon is 112 mmHg, what mass of argon is present in the mixture?

662-341-112= 209 209/760= 0.275atm 0.275/(0.08206(298))=1.125(10⁻²) 1.125(10⁻²)(39.95)= 0.449g

Ammonia,NH₃ can be synthesized by the reaction: 2NO₂(g)+ 5H₂(g) ----> 2NH₃(g)+ 2H₂O(g) Starting with 86.3g NO and 25.6 g H₂, find the theoretical yield of ammonium in grams.

86.3(2molNH₃)/(30.01(2))=2.8757 mol NH₃ 25.G(2molNH₃)/(2.02(5))= 5.0693 molH₃ NO is the limiting reactant bc it has the least amount of product. 2.8757mol(17.03g NH₃) 49.0g NH₃

To inflate a balloon you must do pressure-volume work on the surroundings. If you inflate a balloon from a volume of 0.100 L to 1.85 L against an external pressure of 1.00 atm, how much work is done?

AV= 1.75 L w=-P(AV) -1.75atm -1.75(101.3)= -177 J

Predict the charges of the monatomic (single atom) ions formed by these main-group elements. (a) Al (b) S

Al³⁺ S²⁻

Write the formula for the ionic compounds that form between : aluminum and oxygen calcium and oxygen

Al³⁺ O²⁻ => Al₂O₃ Ca²⁺ O²⁻ => CaO

What are the atomic number (Z), mass number (A), and symbol of the chlorine isotope with 18 neutrons?

Atomic number is 17, mass number is 35

Write a balanced equation for the combustion of liquid methyl alcohol(CH₃OH).

CH₃OH(l) + O₂(g) --> CO₂(g) + H₂O(g) 2CH₃OH(l) + 3O₂(g) --> 2CO₂(g) + 4H₂O(g)

Assign an oxidation state to each atom in each element, ion, or compound. (a) Cl₂ (b) Na⁺ (c) KF (d) CO₂ (e) SO₄²⁻ (f) K₂O₂

ClCl 0,0 0 Na +1 1 KF +1,-1 0 CO₂ +4,-2(2) 0 SO₄²⁻ +6,4(-2) -2 K₂O₂ +1(2),-1(2) 0

Write a balanced equation for the reaction between solid cobalt(III) oxide and solid carbon to produce solid cobalt and carbon dioxide gas.

Co₂O₃(s)+C(s) ---> Co(s)+CO₂(g) 2Co₂O₃(s)+3C(s) ---> 4Co(s)+3CO₂(g)

Copper has two naturally occurring isotopes: Cu-63 with a mass of 62.9291 amu and a natural abundance of 69.17%, and Cu-65 with a mass of 64.9278 amu and a natural abundance of 30.83%. Calculate the atomic mass of copper.

Cu-63= 69.17 / 100= 0.6917 Cu-65= 30.83 / 100= 0.3083 0.6917(62.9291)+0,3083(64.9278)= 63.55 amu

Two samples of carbon dioxide are decomposed into their constituent elements. One sample produces 25.6g of oxygen and 9.60 g of carbon, and the other produces 21.6g of oxygen and 8.10 g of carbon. Show that these results are consistent with the law of definite proportions.

First sample: Mass of oxygen/mass of carbon 25.6/9.60 2.67 or 2.67:1 Second sample: Mass of oxygen/ mass of carbon 21.6/8.10 2.67 or 2.67:1 the ratios are the same so this is consistent with the law of infinite proportions.

Determine whether NH₃ is polar.

H | H---N---H ∙∙ molecular geometry is trigonal pyramidal three dipole moments sum to a net dipole moment. The molecule is polar.

Write the structural formula for water

H-O-H

When a log is completely burns in a campfire, the mass of the ash is much less than the mass of the log. What happens to the matter that composed the log?

Most of the matter that composed the log undergoes a chemical change by reacting with oxygen molecules in the air. The products of the reaction are then released as gases into the air.

Arrange the elements in order of decreasing electronegativity : P, Na, N, Al.

N>P>Al>Na

We put a drop of water into a container and seal the container. The drop if water then vaporizes. Does the mass of the sealed container and its contents change upon vaporization?

No, the mass doesn't change. The water vaporizes and becomes a gas, but the molecules are still present within the flask and have the same mass.

Write a balanced equation for the reaction between aqueous strontium chloride and aqueous lithium phosphate to form solid strontium phosphate and aqueous lithium chloride.

SrCl₂(aq)+Li₃PO₄(aq) -----> Sr₃(PO₄)₂(s)+LiCl(aq) 3SrCl₂(aq)+2Li₃PO₄(aq) -----> Sr₃(PO₄)₂(s)+6LiCl(aq)

Suppose that one of Millikan's oil drops has a charge -4.8x10⁻¹⁹C. H ow many excess electrons does the drop contain?

The drop contains three excess electrons (3 x (-6 x 10⁻¹⁹C)= -4.8 x 10⁻¹⁹C.

Explain the difference between the law of definite proportions and the law of multiple proportions.

The law of definite proportions applies to two or more samples of the same compound and states that the ratio of one element to the other is always the same. The law of multiple proportions applies to two different compounds containing the same two elements (A and B) and states that the masses of B that combine with 1 g of A are always related to each other as a small whole-number ratio.

What prefix multiplier is appropriate for reporting a measurement of 5.57x10⁻⁵m?

The prefix micro(10⁻⁶) is appropriate.

What happens to hte vapor pressure of a substance when its surface are is increased at constant temperature?

The vapor pressure remains the same.

Methanol has a normal boiling point of 64.6°C and a heat of vaporization of 35.2kJ/mol. What is the vapor pressure of methanol at 12.0°C?

T₁=64.6+273= 337.8K T₂=12+273 = 285.2K ln(P₁/P₂)=(-35.2(10³))/8.314(1/285.2-1/337.8) -2.31 P₂/P₁=e⁻².³¹ 75.4 torr

A body-centered cubic unit cell has a volume of 4.32(10⁻²³)cm³. Find the radius of the atom in pm.

V=l³ cbrt(4.32(10⁻²³)= 3.5088(10⁻⁸) r=sqrt(3)l/4 sqrt(3)(3.5088(10⁻⁸)/4= 1.5193(10⁻⁸) 1.5193(10⁻⁸)(0.01)(1)/(1(10⁻¹²)= 152pm

Calculate the wavelength in nm of the red light emitted by a barcode scanner that has a frequency of 4.62(10¹⁴s⁻¹).

____3.00(10⁸)____ 4.62(10⁻⁷) 6.49(10⁻⁷)/10⁻⁹= 649nm

Which statement best describes the difference between a law and a theory? (a) A law is truth; a theory is mere speculation (b) A law summarizes a series of related observations; a theory gives the underlying reasons for them (c) A theory describes what nature does; a law describes why nature does it.

b

What values of l are possible for n=3? (a) 0 (or s) (b)0 and 1 (or s and p) (c) 0,1, and 2 (or s,p, and d ) (d) 0,1,2, and 3 (or s,p,d,and f)

c

Which compound is most likely to contain ionic bonds? (a) CH₄ (b) N₂O (c) MgF₂

c

Which electrons experience the greatest effective nuclear charge? (a) the valence electrons in Mg (b) the valence electrons in Al (c) the valence electrons in S

c

Name the compound CaBr₂.

calcium bromide

What type of bond -ionic or covalent- forms between nitrogen and oxygen?

covalent because the bond is between two nonmetals

These sets of quantum numbers are each supposed to specify an orbital. One set however is erroneous. Which one? (a) n=3; l=0; m₁=0 (b) n=2; l=1; m₁=-1 (c) n=1; l=0; m₁=0 (d) n=4; l=1; m₁=-2

d

What values of m₁ are possible for l=2? (a) 0,1, and 2 (b) 0 (c) -1, 0, and +1 (d) -2,-1,0,+1 and +2

d

Suppose you find a penny in the snow.How much heat is absorbed by the penny as it warms from the temperature of the snow, which is -8.0°C, to the temperature of your body, 37°C? Assume the penny is pure copper and has mass of 3.10g.

delta T = 45°C mCAT 3.10(0.385)(45)= 53.7J

Predict the geometry and bond angles of ICl₄⁻.

electron geometry is octahedral : six e⁻ groups molecular geometry is square planar: four bonding groups and two lone pairs bond angles 90°

Predict the geometry and bond angles of PCl₃.

electron geometry is tetrahedral : four e⁻ groups molecular geometry is trigonal planar: three bonding groups and one lone pair bond angles <109.5

A sick child has a temperature of 40.00 °C. What is the child's temperature in (a) K and (b) °F?

k= °C+273.15 K=313.15 °C=(F-32)/1.8 1.8(°C)=(°F-32) °F=1.8(°C)+32 °F=104.00

Name the compound PbCl₄.

lead(IV) chloride

What is the geometry of the HCN molecule? The Lewis structure of HCN id H-C---N: (a) linear (b) trigonal planar (c) tetrahedral

linear: two electron groups

Name the compound Li₂Cr₂O₇.

lithium dichromate

A man receives a platinum ring from his fiancée. Before the wedding he notices that the ring feels a little tight for its size, and so he decides to determine its density. He places the ring on a balance and finds that it has a mass of 3.15g. He then finds that the ring displaces 0.233cm³ of water. Is the ring made of platinum? (Density of platinum is 21.4g/cm³)

m=3.15g V=0.233cm³ d=m/V 3.15/0.233 13.5g/cm³ The density of the ring is too low for it to be made of platinum.

What is the molarity of a solution containing 25.5 g KBr dissolved in enough water to make 1.75 L of solution?

mm= 119.00 g/mol 25.5g/119.00g= 0.21429 mol 0.21429/1.75= 0.122M

The mass of fuel in a jet must be calculated before each flight to ensure that the jet is not too heavy to fly. A 747 is fueled with 173,231 L of jet fuel. If the density of the fuel is 0.768 g/cm³, what is the mass of the fuel in kilograms?

relationships used: 1 mL=10⁻³L 1mL=1 cm³ 1000g=1kg 173,231x_ 1mL_ x _1cm³_ x _0.768g_ x _1kg_ 10⁻³L 1mL 1cm³ 1000g 1.33x10⁵kg