Midterm
12.76g/ 230 cm3 =
0.055 g/cm3
0.309 mL -0.04 mL =
0.27 mL
0.059 J + 0.16 J +1.2358 J =
1.45 J
Seawater has an average density of 1.03 g/mL. If 1 pound = 453.6 g, what volume of seawater in L has a mass of 100.0 pounds?
100.0 lb seawater * 453.6 g/ 1 lb * 0.001 l/ 1 mL = 44.0 L seawater
A drug comes in a solution that has 50.0 mg of the drug per 100.0 mL of solution. A patient requires 30.0 mg of the drug per day. How many mL of solution are needed to supply the patient for exactly 14 days?
14 days * 30.0 mg drug/ 1 day * 100.0 mL solution/ 50.0 mg drug = 840. mL solution.
How many electrons are in each of the first three orbital shells of neutral phosphorus (P) atom?
1st: 2 2nd: 8 3rd: 5
How many electrons are in each of the first three orbital shells of potassium (K) atom?
1st: 2 2nd: 8 3rd: 8 4th: 1
Typical gasoline has a density of 0.74 g/mL. What volume of gasoline (in gallons) has a mass of 25 pounds? (1 pound = 453.6 g, 1 gallon = 3.785 L) q
25 lb gas * 453.6 g/ 0.74 g gas * 0.001 L/ 1 mL * 1 gal / 3.785 L =4.0 gal gas
If a marathon runner runs at steady pace of 2.7 meters per second, how long (in minutes) will it take her to complete the 26.2 mile race? (1 mile= 1.609 km)
26.2 mile * 1.609 km/1 mile * 1000 m/1 km *1 s/2.7 m* 1 min/60 s = 260 min
253 kg +42.1 kg =
295 kg
3700 cm - 67 cm =
36 cm
(3.5 *10^7) m/s * 0.1245 s=
4.4 *10^6 m or 4400000
128 g /0.0030 mole =
43000 g/mole or 4.3 *10^4 g/mole
If 1 nutritional calorie = 4.184 kiloJouels of energy. How many Joules are there in a 765 Calorie lunch?
765 Cal * 4.184 kJ/ 1 Cal * 1000 J/1 kJ = 3.20 *10^6 J
0.00342 m* 2890 m =
9.88 m2
Write the full atomic symbol of strontium including the protons, electrons and neutrons?
90 2+ Sr 38 p:38 n:52 e:36
Columbia's municipal power plant produces a maximum of 94.6 mega Watts ( MW) of power. How many 175 Watt light bulbs can be powered at the same time?
94.6 MW * 1*10^6 W/1 MW * 1 bulb/ 175 W = 5.41 *10^ 5 bulbs
What is the polyatomic cation?
NH4+ ammonia
what are the polyatomic anions?
OH- hydroxide CO32- carbonate NO3- nitrate SO42- sulfate PO43- phosphate C2H3O2- acetate (also commonly written asCH3CO2-) HCO3- bicarbonate
The initial temperature of a 344-g sample of solid iron is 18.2 ºC. If the sample absorbs 2250 J of heat without melting, what will be the final temperature? (the specific heat capacity of solid iron is 0.449 J/gºC)
Removing heat T will be negative (-) q = m x (T in °C) x s/ ms = T = q/ ms = 2250 J / 344 g *0.449 J/g C T = 14.6 C Tfinal = Tinital +T = 18.2 +14.6 = 32.8 C
A room thermostat is set at 68.0 degrees F. Convert this temperature first to C and then to K . Temp formulas : Tk =273.15 +Tc: Tc =(Tf -32) *5/9; Tf = (Tc* 9/5) +32
Tc = (Tf - 32) *5/9 = (68.0 -32) * 5/9 = 36.0 * 5/9 = 20.0 C Tk = Tc + 273.15 = 20.0 +273.15 = 293.2 K
Average human body temperature is 98.6 F. What is this temperature in C and K?
Tc= (Tf -32) * 5/9= (98.6 -32) *5/9 = 66.6 *5/9 = 37.0 C Tk = Tc +273.15 = 37.0 + 273.15 = 310.2 K
How many electrons are in each shell for: a) f b) Na c) Fe d) I
a) 1st; 2 2nd: 7 7 valence electrons (9e-) b) 1st: 2 2nd: 8 3rd: 1 1 valence electron ( 11e-) c) 1st: 2 2nd: 8 3rd: 8 4th 8 (26e-) d) 1st: 2 2nd: 8 3rd:8 4th : 8 5th: 17 (53e-) column 7
State the number of significant figures? a) 3500 L b) 0.00001 degrees Celsius c) 20.00 s
a) 2 b) 1 c) 4
Rank the following atoms from 1-3 where 1 has the lowest ionization energy and 3 has the highest ionization energy. a) 0 b) F c) S
a) 2 b) 3 c) 1
State the number of significant figures? a) 2500 g b) 0.0380 m c) 149 miles d) 0.2308 g e) 1.200 millimeters
a) 2 b) 3 c) 3 d) 4 e) 4
Rank the following atoms from 1-3 where 1 has the lowest ionization energy and 3 has the highest ionization energy. a)Na b) Mg c) K
a) 2 b) 3 c) 1 Explanation: same row : Mg > Na (more protons holds it electrons more tightly) Same column: Na > K ( valence electrons in lower shell, harder to remove)
Write in scientific notation: a) 260000 kg b) 400 mm( with 2 S.F) c) 0.00050 m
a) 2.6 *10^5 kg b) 4.0 *10^2 c) 5.0 *10^-4 m
What charges and names will monotonic ions of the following elements have: a) nitrogen (N) b) potassium (K) c) barium (Ba) d) sulfur (S) e) iodine (I)
a) 3- nitride b) + potassium ion c) 2+ barium ion d) 2- sulfide e) - iodide
Round each value as specified: a) 319 cm( round tens place) b) 2500 ft ( round to 1 S.F) c) 0.05045 L( round to 2 S.F) d) 399 m (round to tens place)
a) 320cm b) 3000 ft c) 0.050 L d) 4.0 *10^2 m
Write the full atomic symbol: a) A neutral atom has 3 protons and 4 neutrons. b) 34 protons 43 neutrons c) 82 protons 126 neutrons
a) 7 Li 3 b) 77 Se 34 c) 208 Pb 82
Write the correct chemical formula for the following compounds: a) aluminum carbonate b) ammonium phosphate c) chromium (III) floride d) dichlorine monoxide
a) Al2(C03)3 b) (NH4)3PO4 c) CrF3 d) Cl20
Name of the cation ( minus the word ion) followed by the name of the anion: a) Alf3 b)Cu(OH)2 c) calcium nitrate d) iron (III) oxide
a) Al3+ F- =aluminum fluoride b) Cu2+ Oh- = copper (II) hydroxide c) C2+ N03- = Ca(N03)2 d) Fe 3+ 02- =Fe203
Which has the largest first ionization energy and why? a) Si vs C b) Si vs Al
a) C valence electrons in C in a lower shell b) Si has more protons so holds it valence electrons more tightly.
Which has the largest radius and why? a) I vs Br b) Ca vs K c) Ca vs Br
a) I because has electrons in higher shell b) K has fewer protons in nucleus so weaker attraction to e- c) Ca has fewer protons ( fewer to the left)
For each pair of atoms, which one is larger ( has a bigger atomic radius) and explain why it is larger based on its electrons and protons. a) N vs. O b) B vs. Al
a) N has fewer protons in its nucleus so hold its electron less tightly. ( both have 2nd shell valence electrons) b) Al has 3rd shell valence electron ( both on the same column and B has 2nd shell)
Write the correct chemical formula for the following compounds: a) sodium phosphide b) dinitrogen tetroxide c) lead (II) carbonate d) calcium nitride
a) NA3P b) N204 c)PbCo3 d) Ca3N2
Write the formulas of the following ions: a) selenide b) lithium ion c) titanium (IV) ion d) strontium ion
a) Se2- b) Li+ c) Ti4+ d) Sr2+
For each pair of atoms, which one is larger ( has a bigger atomic radius) and explain why it is larger based on its electrons and protons. a) Mg vs Sr b) P vs Cl
a) Sr has 5th shell valence electrons. ( Same column and Mg only in 3rd shell) b) P has fewer protons in its nucleus so holds its electrons less tightly. ( same row)
Match the statement with the chemical family or classification which best fits ( choose from alkali metals, alkaline earth metals, transition metal, halogens, inert gas or metalloids: a) its two most important elements are MG and Ca b) They include copper (Cu) sliver (Ag) and gold (Au) c) They found in column 2 of the periodic table d) They normally gain one electron in forming an ion
a) alkaline earth metals b) transition c) alkaline metals d) halogens
Name the chemical name and cation and anion for the following binary ionic compounds: a) NaBr b) PbS04 c) BaCl2 d) (NH4)2S
a) cation Na+, anion Br- sodium bromide b) caution Pb2+, anion So42- lead(II) sulfate c) cation Ba2+, anion Cl- barium chloride d) cation NH4+ , anion S2- ammonium sulfide
Label each as most likely a chemical or physical change: a) photosynthesis converts water and carbon dioxide into oxygen and sugar molecules b) a light bulb filament is a gray metal when the bulb is turned off, glows bright white when the bulb is on, and then returns to gray when the bulb is off. c) after being struck by lightning a large balloon filled with hydrogen gas burns into flames and burns completely over several minutes. d) a cup of household bleach changes the color of the shirt from dark green to pale green. e) water vapor in your exhaled breath condenses to liquid mist in the air on a cold day. f) a sliver wire glows bright orange when electricity runs through it, but returns to its original color when the electricity is turned off.
a) chemical b) physical c) chemical d) chemical e) physical f) physical
Label each as most likely a chemical or physical change: a) gasoline is burned in a car's engine, producing exhaust vapors of carbon dioxide and water. b) heat is added to a colorless liquid, causing bubbles of gas to form. c) Mercury metal reacts with sulfur at high temperatures to produce a reddish solid (cinnabar) d) plants combine carbon dioxide, water and sunlight to make carbohydrates and oxygen e) an egg; albumen solidifies and turns white when placed on a hot stove f) grapes ferment to make wine
a) chemical b) physical ( boiling) c) chemical d) chemical e) chemical f) chemical
Label each as an example of an element, compound, homogeneous mixture or heterogeneous mixture: a) calcium nitrate 9 Ca(NO3)2) b) saltwater (salt fully dissolved in water) c) chromium (Cr) d) ammonia (NH3) e) blood f) Glucose
a) compound b) homogeneous mixture c) element d) compound e) heterogeneous mixture f) compound
Label each as an example of an element, compound, homogeneous mixture or heterogeneous mixture: a) water (H20) b paper c) Air (02, N2, Ar, H20 ect) d) Copper (Cu) e) Carbon dioxide (C02) f) Gasoline ( C X Hy )
a) compound b) homogeneous mixture c) homogeneous mixture d) element e) compound f) homogeneous mixture ( mixture of hydrocarbons)
Label each process as endothermic or exothermic: a) a stick of dynamite explodes, releasing a large amount of energy. b) a block of dry ice (solid C02) slowly changes to gas when left out at room temperature. c) perspiration evaporates, cooling your skin. d) wood burns, producing heat.
a) exothermic b) endothermic c) endothermic d) exothermic
Match the statement with the chemical family or classification which best fits ( choose from alkali metals, alkaline earth metals, transition metal, halogens, inert gas or metalloids: a) They have a full valence shell as neutral atoms b) They are found in column 7 (by the numbering used in class) of the periodic table c) they normally lose two electrons in forming an ion.
a) inert gases b) halogens c) alkaline earth metals
Give the correct chemical name for the following compounds: a) Mg(NO3)2 b) SF4 c) Fe(C2H302)2 d) Cu3p e) V(SO4)2
a) magnesium nitride b) sulfur tetrafluoride c) iron (II) acetate d) copper (I) phosphide e) vanadium (IV) sulfate
Give the correct chemical name for the following compounds: a) NCI3 b) Ba(OH)2 c) CoSO4 d) (NH4)2Se e) K3P
a) nitrogen trichloride b) barium hydroxide c) cobalt (II) sulfate d) ammonium seleuide
Give the name for each of the follwing binary (two element) molecule compounds: a) NF3 b) HI c) N205 d) P4S3 e) H20 f) K25 g) Na3Po4
a) nitrogen trifloride b) hydrogen monodide OR hydrogen iodide c) dinitrogen pentoxide d) tetraphosphorus trisulfide e) dihydrogen monoxide f) potsdium sulfide g) sodium phosphate
Give the number of protons neutrons and electrons in: a) 14C b) 31P c) 235U
a) p: 6 N:8 e:6 carbon 14 b) p:15 n:16 e:15 phosphorus 31 c) p:92 n:143 e:92 uranium 235
Give the total protons and electrons to the following ions: a) F- b) Ca2 c) P3- d) Pb4=
a) p: 9 e: 10 (2.8) full valence shell b) p: 20 e: 18 (2,8, 8) 1st 3 shells c) p: 15 e: 18 (2,8,8) 1st 3 shells d) p; 15 e; 78 ( transition medal ( not as solid) tend to form more than 1 charge of ion wont have full shell)
Solid lead has a specific heat capacity of 0.128 J(g C) a) how much heat ( in kJ) must be added to 475 g of solid lead to raise its temperature from 22.0 C ti 100.0 C (not hot enough to melt the lead)? b) if the same amount of heat was added to an equal mass of liquid water (also starting at 22.0 C) would any of the water boil? (specific heat capacity of water = 4.184 J/ (g C) )
a) q = m x (T in °C) x s T= 100.0 C - 22.0 C = 78.0 C q= 475 g * 78.0 C * 0.128 J/g C * 1 kJ/1000 J = 4.74 kJ b) no, since waters specific heat cap is much higher than leads, temp change would lower for water, so it wouldn't reach its boiling point of 100 C.
a) Given that the specific heat capacity of liquid water is 4.184 J/(gºC), how much heat (in J) must be added to raise the temperature of a 580 g sample of water from 22.1 ºC to 50.0 ºC? b) If the same amount of heat is added to a 390 g piece of solid copper, the temperature of the copper increases from 22.1 ºC to 476 ºC (not high enough to melt copper). What is the specific heat capacity of solid copper?
a) q = m x (T in °C) x s T= 50.0 -22.1 =27.9 C q = 580 g * 27.9 C * 4.184 J/ g C = 68000 J = 68 kJ b) T = 476 -22.1 = 453.9 = 454 C q = m x (T in °C) x s/ m x T = m x T x q = s = 6800 J / 390 g *453.9 C s = 0.38 J/g C
A pure substance containing only one type of atom is called a(n)
element
When the temperature of any substance increases, the particles making up the substance move at ________ average speed.
faster
The only naturally occurring isotopes of Li are lithium -6 and lithium -7. Which isotope is more common?
lithium -7 (avg. mass of Li is closer to 7 than 6)
The smallest possible unit of a compound is called a(n)
molecule
The specific heat capacity of liquid Mercury is 0.139 J/g C. How many kJ of heat are needed to raise temperature of 250 g of mercury from 22.1 C to 100.0 C?
q = m x (T in °C) x s T= 100.0 - 22.1 = 77.9 C q = 250 g * 77.9 C *0.139 J/ g C * 1kJ/1000 J = 2.7 kJ
What quantity of heat is evolved (i.e. removed from the water) when 47 kg of water at 0.0 ºC completely freezes? The heat of fusion for water is 333 J/g.
q = m ∙ Hvap (for boiling) 47000 g * 2260 J/1 g = 1.1 * 10^8 J or 110000 kJ
When 250 grams of Hg is at its melting temperature of -38.83 degrees Celsius how much heat (in J) is required to turn all of it from solid to liquid without changing the temperature? Mercury (Hg) has normal melting point of -38.83 degrees Celsius and normal boiling point of +356.73 degrees Celsius. Heat fusion is 11.4 J/g.
q= m*temperature (triangle symbol)Hfus = 250 g *11.4 J/g = 2900 J
What quantity of heat is evolved (i.e. removed from the water) when 47 kg of water at 0.0 ºC completely freezes? The heat of fusion for water is 333 J/g.
Freezing q = m ∙ Hfus (for melting) = 47 kg * 1000 g/ 1kg * -333 J/ 1g = 1.6 * 10^7 J or (-16000kJ)
The two most important elements are?
Mg and Ca
