CHM101 Exam 1 (ch.1-3)
What is the charge of the following Type I metal Ba?
+2 (in Group IIA)
What is the charge for the following non-metal: C?
-4 Group 4A subtract 8 so 4 is charge and it is negative because it is a anon-metal.
What is the correct formula for a potassium ion with 18 electrons?
..
In order, what is the freezing point and boiling point of water according to the Celsius scale?
0-100
What is the correct decimal representation of 1.201 x 10^-7
0.0000001201
How many liters are in 333 mL? Enter your answer as a number only.
0.333
When 49.5 J of heat was transferred to 7.3 g of iron at 22 degrees Celsius, the temperature of the iron increases to 37 degrees Celsius. What is the specific heat of iron in J/g/C?
0.45
In the custom section of the PhET lab, what is the mass of the styrofoam in kg? Enter your answer as a number only with two sig figs.
0.75
According to the PhET Density lab, what was the density of the ice?
0.92
What is the density of 96 mL of a liquid that has a mass of 90.5 g?
0.94 g/mL
The name for PbCl4 is
1. Lead (IV) chloride Identify compound: Binary Type II ionic compound Identify metal (cation): Lead Identify anion (non-metal): chlorine Charges must cancel: If Cl has -4 Pb must be +4 to cancel out so Lead needs Roman numeral of (IV) Change ending of non-metal to -ide: chloride Lead (IV) chloride Pb is a Type II metal. 5.
How many atoms are in 67.9 g of oxygen gas?
1.28x10^24 Oxygen gas is O2 so you need the mass of 2 oxygens. 1. 67.9 g O2 x 1 mol O2/32 g O2 x 6.022 x 1023 atoms of O2/ 1 mol O2= 1.28 x 10 24 atoms of oxygen gas
What is the density (g/mL) of an object that has a mass of 14.01 grams and when placed into a graduated cylinder, causes the water level to rise from 25.2 mL to 33.6 mL? Enter your answer as a number with correct sig figs only.
1.7
The number of moles of O in 1.7 mol of CaCO3 is _______ moles of O
1.7 mol CaCO3 x 3 mol O/ 1 mol CaCO3= 5.1 mol O Use the following conversion factor: 3 mol O: 1 mol of CaCO3 (from chemical formula 16. Calculate the mass percent of Cl in freon-114 (C2Cl4F2) 4 x molar mass Cl= 4 (35.45)= 141.8g molar mass C2Cl4F2= 2 (12.01)+ 4 (35.45) + 2 (19.00)= 203.8 g 141.8/203.8g x 100%= 69.58%
What is the mass of just the chewed gum? Use the data from above about the mass of the chewed gum and the wrapper as well as the data regarding the mass of the wrapper alone to answer. Enter a number only.
1.74 g- .26 g= 1.48 g
Calculate the mass in grams of 1.75 mol of water. Enter your answer as a number with three sig figs only
1.75 mol H2) x 18.02 g H2O/ 1 mole H2O=. 31.5 g H2O You need to calculate molar mass of H2O from periodic table which is 18.02 g
How many milliliters are in 17.5 L?
1.75 x 10^4
How many inches are in 25.8 cm?
10.2
How much heat (kJ) is needed to raise the temperature of 100.0 grams of water from 25 degrees Celsius to 50 degrees Celsius?
10.5
How would the number 1.09 x 10 1 be expressed in decimal form?
10.9
What is the correct prefix for femto?
10^-15
What is the correct multiplier for the prefix micro?
10^-6
An object weighing 1.840 kg has a volume of 0.0015 L , what is the density of the object in g/mL? Express your answer as a number with correct sig figs only without scientific notation.
1200.0
The formula mass of nitrogen triiodide is
14.01+ 126.90x3= 394.71 Use five sig figs This is NI3 N= 14.01g I= 126.90 g
How many low dose 81 mg aspirin tablets can be made from 1.21 kg of aspirin? Express your answer as a number with correct sig figs only. Do not use scientific notation.
15000.0
Calculate the formula mass of carbon tetrachloride. Answer as a number with four sig figs only.
153.8 1. 12.01+ 4 (35.45)= 153.8 CCl4 Carbon has 12.01 g and Cl has 35.45 g. 2.
What is the volume of 12.8 g of liquid that has a density of 0.789 g/mL? Express your answer as a number only with the correct number of sig figs.
16.2
How many aluminum atoms are in an aluminum can with a mass of 16.2 g?
16.2 g Al X 1 mol Al/ 26.98 g Al X 6.022 x 10 23 Al atoms/ 1 mol Al= 3.62 x 10 23 Al atoms
A n elements has two isotopes, making up 50% of the population. Isotope 1 has a mass of 80.0 amu, Isotope 2 has a mass of 85.0 amu. Calculate the atomic mass of the element.
165 amu
According to the PhET density lab, gold was the most dense object. What was its density? Answer as a number with three sig figs only.
19.3
According to the PhET Density Lab, what was the density of the green object in the same mass section of the lab?
2
Using its placement on the periodic table, what is the charge on the barium ion?
2+
What is the charge on the ion formed by selenium?
2-
What is the answer to the following equation with correct number of significant figures: (4.123 x 0.12) + 24.2=
24.7
What is the final temperature of 25.0 grams of water at 22.0 degrees Celsius after it absorbs 454 J of heat? Enter a number only.
26.3
What is the mass percent of carbon in carbon dioxide? Enter your answer as a number only with two sig figs.
27% CO2= 12g+ 16 x 2g= 44 g Carbon is 12g/ 44 g x 100= 27 % Carbon dioxide is CO2. Carbon weighs about 12 grams and oxygen weighs about 16 grams according to the periodic table.
What is the value of 19 degrees Celsius on the Kelvin scale? Enter a number only.
292.0
How many significant figures should be reported in the answer to the following calculation? (8.50) x (29.0) x (1.0947) =
3
In the number 48.93, which digit is estimated?
3
What is the correct number of significant figures in 865,000?
3
How many grams of sulfur are in 1 mole of sulfur?
32.06 g
How many electrons are in Br-?
36
Given the density of Au is 19.3 g/cm^3 determine the mass of gold in an ingot with the dimensions of 10.0 in x 4.00 in x 3.00 in. Give your answer as a number with correct sig figs only. Do not use scientific notation.
38000.0
hat is the correct number of significant figures in the number 0.002320?
4.0
How many microliters are in 41.0 ml?
4.10 × 10^4
A room has dimensions of 10.0 ft x 20.0 ft x 8.00 ft. What is the volume of the room in cubic yards if 1 foot = 3 yards? Express your answer as a number only with correct sig figs. Do not use scientific notation.
43200.0
What is the correct scientific notation for 0.00050210?
5.0210 x 10 ^−4
How many moles are in 34.5 atoms of oxygen? 5.73x10^-23moles Use Avogadro's number as a conversion factor.
5.73X 10 -23 moles of oxygen 34.5 atoms oxygen x 1 mol oxygen/ 6.022 x 10 23 atoms of oxygen
Calculate the number of moles of sulfur in 57.8 g of sulfur
57.8 g S x 1 mol S/ 32.06 g S= 1.80 mol S
What is the formula mass of table salt? Enter your answer as a number with four sig figs only.
58.44 22.99+ 35.45= 58.44
What is the mass of the gum in grams? Use the data given above for the mass of the gum and wrapper and mass of wrapper alone. Enter the number only.
6.45 g- 0.26 g= 6.19 g Subtract the mass of gum and wrapper from mass of wrapper.
What is the value of 335 K on the Celsius temperature scale? Enter your answer as a number only.
62.0
Given that the molecular mass of beryllium is 9.01 grams, which of the following isotopes would you expect to have the greatest natural abundance?
Be-9
In the PhET Density lab, which of the following objects sunk in the custom section of the lab?
Brick
Which of the objects in the custom section of the PhET density lab had a density of 2.00 in kg/L? Enter your answer as one word.
Brick
What is the formula mass for Calcium chloride? Use 40.08 for mass of calcium and 35.45 for mass of chlorine. Write the number only with five sig figs.
Ca= 40.08 g + Cl= 35.45 x 2= 110.98 g
Write the name for CaCl2
Calcium chloride Calcium is a Type I metal so we do not have to write a Roman numeral. Cl is chlorine so we change that ending to -ide for calcium chloride.
What is the name for CO? Enter the two words only:
Carbon Monoxide (or molecular compound, use names with ide ending for second non-metal. Use mono to indicate one for second element)
Which statement below best describes the process of the paint on a vehicle fading over time?
Chemical change because the paint molecules are changing composition.
The formula for perchloric acid is
ClO4 is perchlorate-change ending to ic and add acid.
Which statement below is not consistent with the theory proposed by Rutherford?
Electrical charge is a fundamental property of protons and electrons in which like charges repel and opposite charges attract.
Naphthaene is a compound containing carbon and hydrogen that is used in mothballs. Its empirical formula is C5H4 and its molar mass is 128.16 g/mol. Its molecular formula is
Empirical formula molar mass= 5 (12.01) + 4 (1.01)= 64.09 g /mol 128.16 g/mol/ 64.09 g/ mol =2 C5H4 X2= C10 H8 (Hint:The molar mass of C5H4= 64.09 g/mol)
The formula for ammonium nitrate is
H4NO3 This is an ionic compound with two polyatomics.This is an ionic compound with two polyatomics so not binary. Formula for first polyatomic and charge: ammonium NH4 1+ Formula for second polyatomic and charge: nitrate NO3 1- Balance charges: already balanced so answer is NH4NO3
What is the formula for Hydroiodic acid?
HI This is a binary acid..two elements start with H. H has +1 charge iodic comes from iodine which has a -1 charge. Charges balance so formula is HI.
What is the correct chemical symbol of mercury? Enter symbol only.
Hg
Looking at your data from the same mass and same volume section of the PhET lab, what must be true about the density of an object in order for it to float?
It must have a density of 1
Which of the following formulas below represent a binary ionic compound with a Type I metal?
KCl Binary -two elements with one metal from Groups I, II, or IIIA and a non-metal. K is a Type I metal. Cl is a non-metal with two elements.
What is the formula for Magnesium carbide?
Mg2C Magnesium is a Type I metal with a +2 charge. Carbon has a -4 charge based upon its location in the periodic table. With criss cross method, it becomes Mg4 C2 but those subscripts can be reduced to Mg2C.
What is the formula for Maganese (IV) carbide?
MnC This is a Type II metal so we know its charge from the Roman numeral which is +4. Manganese is Mn. Carbon has a -4 charge based upon its location in the periodic table so +4 and -4 cancel out and both become one so no subscripts needed so MnC is the answer. This is a Type II metal so we know its charge from the Roman numeral which is +4.
You decompose a compound containing nitrogen and oxygen in the lab and produce 24.5 g of nitrogen and 70.0 g of oxygen. The empirical formula for this compound is
N2O5 Convert masses to moles: 24.5 g N x 1 mol N/ 14.01 g N= 1.75 mol N 70.0 g O x 1 mol O/ 16.00 g O= 4.38 mol O Write formula: N1.75O4.38 Divide all subscripts by smallest subscript and round N1O2.5 If subscripts do not round to whole numbers, multiply all subscripts by small whole number so N1O2.5 x2= N2O5
Which state of matter has atomic spacing that is far apart and has a definite shape?
NONE A liquid B solid C gas
hich of the following statements about matter is false?
NONE: A Matter occupies space and has mass. B Matter exists in either a solid, liquid, or gas state. C Matter is ultimately composed of atoms.
A block has is 2.2 cm x 3.0 cm x 1.5 cm and a mass of 12.4 grams. Will the block float in water and why?
No, because the density of the block is 1.3 g/mL which is greater than the density of water.
Which of the following statements is NOT a part of the rules for determining significant figures?
Non-zero digits at the end of a number are not significant. so.. it is determined by: Zeroes between two numbers are significant and Zeroes to the left of the first non-zero number are not significant.
What is the formula mass of sulfur dioxide? Answer as number only with four sig figs.
One sulfur two oxygens SO2= 32.06+ 16 x 2= 64.06 g
Which of the formulas below represent a polyatomic ion?
SO4 SO4 is sulfate with a charge of -2.
What is the difference between a molecular formula and an empirical formula?
The molecular formula is a multiple of the empirical formula.
The name for HC2H3O2 is
acetic acid The oxyanion (Polyatomic) is acetate, which ends in -ate; therefore, the name of the acid is acetic acid.This is an oxyacid.
Group IA elements are also called:
alkali metals
Mg is a member of what family?
alkaline earth metals
What is an atom called when it gains an electron? Answer with one word only.
anion
Isotopes are :
atoms of the same element that have different number of neutrons
What is the resulting particle called when an atom loses an electron?
cation
What is a pure substance composed of?
composed of only one type of atom or molecule
What is a pure substance?
composed of only one type of atom or molecule.
Which statement below accurately describes the contributions of Thomson?
discovered the existence of electrons
Given the following list of densities, which materials would float in a molten vat of lead provided that they do not themselves melt? Densities: g/mL: lead= 11.4; glass= 2.6, gold= 19.3, charcoal= 0.57, platinum = 21.4. Enter your answer as a word only. If two or more items would float include the word and between those two items.
glass and charcoal
What is the name of HBr?
hydrobromic acid Binary acid add hydo bromine becomes bromic and add acid to end.This is a binary acid so we start with hydro and add ic acid to the second element)
Which of the following is not a correct name, symbol combination?
iron, I
Which type of energy is associated with motion?
kinetic
How does volume relate to density in the PhET density lab?
larger volume, lower density
The common English unit in which the speed of an automobile is expressed is miles/hr. What is the standard set of SI units for speed?
m/s
What is the standard SI unit for length?
meter
How would you classify rocky road ice cream?
mixture-heterogeneous
How would you classify salt water?
mixture-homogeneous
Group 8A Elements are also called
noble gases
Which statement accurately describes the contributions of Dalton?
proposed the modern atomic theory
According to your results from the PhET Density Lab, 2. How does the density of a large piece of aluminum compare to a small piece?
same density
The name for SF6 is
sulfur hexaflouride Identify type: binary molecular Name first non-metal: sulfur Name second non-metal : flourine Change ending of second non-metal to ide: fluoride Use prefixes: six is hexa sulfur hexaflouride ( a binary molecular compound)
Which of the following items is a chemical property?
tarnishing of copper
