Exam 1 (conversions, sig figs, isotopes, molecular/empirical)
.057 x (17.00009 + 32052.10)=
What is 1800? (2 sig figs)
Name each compound AND say if it is soluble if ionic compound, or weak/strong if an acid.
1. S5Br
2. HC2H3O2
3. (NH4)3PO4
4. Be(OH)2
5. HF
1. Pentasulfur Monobromide
2. Acetic acid (weak acid= does not dissociate)
3. Ammonium Phosphate (soluble)
4. Beryllium Hydroxide (insoluble)
5. Hydrofluoric acid (weak acid)
7. In a mixture of the two gases, the partial pressures of CH4 and O2 are 0.175atm and 0.250 atm, respectively. What is the mole fraction for each of the gases?
CH4= 0.412
O2= 0.588
An element that has the valence electron configuration ns2np5 belongs to which group?
Which one of the following ions is isoelectronic with a noble gas?
(a) Sc2+ (b) Y2+ (c) Fe3+ (d) Br- (e) Sn2+
3. Write the shorthand electron configuration AND the orbital diagram for Mn2+
1. What is halogen group?
2. What is d?
3. [Ar]3d5
Label IMFs from weakest to stronges (include ion-dipole)
london --> dipole-dipole --> Hbonding --> ion-dipole
Write isotopic symbols in the form for each isotope (mass on top, # on bottom)
The copper isotope with 34 neutrons
The potassium isotope with 21 neutrons
The argon isotope with 22 neutrons
1. Cu6329
2. K4019
3. Ar1840
Balance the following equation:
___C7H6O2 + ___O2 → ___CO2 + ___H2O
2, 15, 14, 6
To decompose 22.56g of PCl3 (137.3g/mol) requires ___ kJ of energy
4PCl3 → P4 + 6Cl2 H= +1207kJ
What is H= 49.5kJ?
1. F2
2. CH2O
3. NH3
1. linear, nonpolar
2. polar, trigonal planar
3. polar, trigonal pyramidal
Find out if these combined compounds would make a homogenous solution or not. Then write which IMF they have.
CCl4 and H2O
KCl and H2O
2. homogenous. london, dipole-dipole, H bond, ion-dipole
Convert 85.6 ft³ into mL with correct number of sig figs
85.6ft³ x (12in/1ft)³ x (2.54cm/1in)³ x (1mL/1cm³) = 2423922.1 = 2420000 =
What is 2.42 x 10⁶?
Write the NET ionic equation for:
Hydrochloric acid reacts with ammonia.
What is
H+(aq) + NH3(aq) → NH4⁺(aq)?
1. The lower the temperature the slower the average velocity. True or False?
2. The ideal gas law works best a ____ temperature and a ____ pressure
3. A 2.5 mol sample of neon gas in a 5.0 L flask has __________pressure as a 2.5 mol sample of argon gas in a 5.0 L flask at the same temperature.
1. True, directly proportional
2. The ideal gas law works best a _high___ temperature and a __low__ pressure
3. The same pressure
Draw best lewis structure for [NO2]-1 and explain why.
O-N=O
because formal charges are -1, 0, 0
and O is most electronegative with most negative charge.
Nitrogen has a normal boiling point of 77.3 K and a melting point (at 1 atm) of 63.1 K. Its critical temperature is 126.2 K and its critical pressure is 2.55 x 104 torr. It has a triple point at 63.1 K and 94.0 torr. Sketch the phase diagram for nitrogen. Does nitrogen have a stable liquid state at 1 atm?
What is yes?
Bromine has two naturally occurring isotopes (Br-79 and Br-81) and has an atomic mass of 79.904 amu. The mass of Br-81 is 80.9163 amu, and its natural abundance is 49.31%. Calculate the mass and natural abundance of Br-79. Answer in 4 sig figs.
What are 50.69% and 78.92 amu?
What is the percent yield if 55.86g of iron is collected when 102.36g of iron(III) oxide were reacted with 51.54g of carbon monoxide gas?
What is 81.5%?
A 7.9g sample of solid NaOH (39.97g/mol) is dissolved in enough water in a coffee cup calorimeter to make 175mL of solution. If the temperature increases from 23C to 35C, what is the change of H for in kJ/mol of NaOH? Assume density is 1g/mL and heat capacity is 4.18J/g*C.
-44kJ/mol
Rank the ionic compounds to greatest lattice energy: K2O FeO and FrI
FrI< K2O< FeO
How much heat (in kJ) is required to warm 10.0 g of ice, initially at -10.0oC, to steam at 110.0oC? The heat capacity of ice is 2.09 J/g*oC, and that of steam is 2.01 J/g*oC.
What is 30.5kJ?
Combust 0.1156g of compound containing only C,H,N. You capture 0.1638g CO2 and 0.1676g H2O. What is the empirical formula of the compound?
What is CH5N?
350 g of silver reacts with 100 grams of chlorine gas and produces silver (I) chloride. How many moles of excess reactant will there be?
0.45 moles of silver
When 1.01g of C12H22O11 undergoes combustion in a bomb calorimeter, the temperature rises from 24.92 degrees Celsius to 28.33. Find Erxn for the combustion of sucrose in kJ/mol. The heat capacity of the calorimeter is 4.90 kJ/degrees C.
Using the bond enthalpies provided, calculate ΔH for the following reaction. CH3CH3 + Br2 → CH3CH2Br + HBr
What is -33kJ?
List the substances BaCl2, H2, CO, HF, and Ne in order of increasing boiling points and explain how you arrived at your answer.
BaCl2 > HF > CO > Ne > H2
Barium chloride is ionic (ionic bonding is stronger than any form of IMF), HF is second because of its hydrogen bonding. CO > Ne >H2 because larger mass = more dispersion = stronger attraction to overcome to reach boiling point.