Chem Final Test #2

according to the octet rule, strontium (Sr) will form which of the following monoatomic ions a. Sr 2- b. Sr 3+ c. Sr 2+ d. Sr 3-

Sr 2-

if one starts with 10.0 g of a radioactive substance, how much will remain after 3 half lives a. 1.25 g b. 2.50 g c. 3.33 g d. 5.00 g

a. 1.25 g

how many total electrons are contained in sulfide ion 32 S 2- 16 a. 18 b. 14 c. 30 d. 16

a. 18

what is the mass in grams of 3 moles of calcium carbonate, CaCO3, a common antacid a. 300 g b. 150 g c. 100 g d. 68 g

a. 300 g

the formula of a phosphate ion is a. PO4 3- b. P 3- c. HPO4 2- d. H2PO4 -

a. PO4 3-

an isotope of sodium contains 11 protons and 12 neutrons a. atom also contains 11 electrons b. atom also contains 12 electrons c. the atom also contains 23 electrons d. there are no factors related to the 11 protons and 12 neutrons

a. atom also contains 11 electrons

proper name for P2O5 a. diphosphorus pentoxide b. phosphorus pentoxide c. phosphate oxide d. phosphorus oxide

a. diphosphorus pentoxide

the name of the compound Na2CO3 is a. sodium carbonate b. disodium carbonate c. sodium bicarbonate d. disodium bicarbonate

a. sodium carbonate

how many carbon atoms are present in 30 moles of carbon a. 1.20 * 10^1 b. 1.80 * 10^25 c. 3.60 * 10^2 d. 6.02 * 10^23

b. 1.80 * 10^25

Ethanol, C2H5OH, is found in alcoholic beverages. if a 125 g sample is pure ethanol, how many moles of ethanol are present a. 0.419 moles b. 2.72 moles c. 5750 moles d. 46.3 moles

b. 2.72 moles

iron-59 has a halflife of 45 days. how much of a 50.0 g sample would remain after 180 days a. 1.00g b. 3.13 g c. 25.0 g d. no way to determine

b. 3.13 g

formula of calcium sulfate is a. CaSO3 b. CaSO4 c. CaS d. CaS2

b. CaSO4

formula for ammonium chloride is a. AlCl3 b. NH4Cl c. NCl d. AmCl

b. NH4Cl

gamma rays require a thick slab of concrete or lead to block them because they a. have the lowest energy b. are so energetic that they have a very high penetrating power c. are large in size d. are small in size

b. are so energetic that they have a very high penetrating power

mass in grams of one mole of an element is the element's ___ a. atomic number b. atomic weight c. molar mass d. isotope number

b. atomic weight

a compound is a. two or more elements well mixed b. two or more elements combined chemically c. two or more elements carrying a positive charge d. a physical blend of two of more elements

b. two or more elements combined chemically

number of atoms present in 20 gram sample of lithium a. 1.38 * 10^2 b. 1.20 * 10^25 c. 1.70 * 10^24 d. 4.00 * 10^24

c. 1.70 * 10^24

what is the molar mass of magnesium chloride a. 59.8 g/mol b. 90.40 g/mol c. 95.30 g/mol d. 125.90 g/mol

c. 95.30 g/mol

chose the formula of cobalt (II) nitrate a. CoN b. Co2NO3 c. Co(NO3)2 d. Co(II)(NO3)2

c. Co(NO3)2

which is not an element a. sodium b. iron c. air d. carbon

c. air

the compound BaBr2 is named a. barium dibromide b. barium (II) bromide c. barium bromide d. barium bromate

c. barium bromide

difference between an ionic bond and a covalent bond a. ionic bonds commonly occur between two metals and covalent bonds occur between metals and nonmetals b. ionic bonds are between atoms that can share electrons; covalent bonds are between atoms that will donate/accept atoms c. covalent bonds come about because of a sharing of electrons; ionic bonds do not d. ionic bonds are between smaller atoms; covalent bonds are between large amtoms

c. covalent bonds come about because of a sharing of electrons; ionic bonds do not

name of the compound N2O4 a. nitrogen oxide b. nitrogen tetraoxide c. dinitrogen tetraoxide d. nitrogen dioxide

c. dinitrogen tetraoxide

what is the proper name of the compound FePO4 a. iron phosphide b. iron (III) phosphide c. iron (III) phosphate d. iron phosphorus tetraoxide

c. iron (III) phosphate

where are the metals located on the periodic table of elements a. on the right side of metalloid line b. on the last group of the periodic table c. on the left side of metalloid line d. in the two sections separated from the rest of the table

c. on the left side of metalloid line

subatomic particle with a positive charge is ___ a. electron b. neutron c. proton d. cation

c. proton

periodic table of elements does not list whole numbers for atomic weights. why a. atomic weights are not predictable b. atomic weights include protons and neutrons at 1 amu each, but they also include electrons, which weight a lot less than one c. the atomic weight is the weighted average of the masses of the known isotopes of an element d. the atomic weights do not include isotopes

c. the atomic weight is the weighted average of the masses of the known isotopes of an element

two atoms that are isotopes of an element contains a. the same number of electrons and neutrons b. the same number of protons and neutrons c. the same number of protons and different number of neutrons d. different numbers of protons

c. the same number of protons and different number of neutrons

radioisotopes with short half-lives are used in diagnostic tests because a. they have high energy b. they are inexpensive c. they do not post health risks by being present long after use d. they have less penetration ability

c. they do not post health risks by being present long after use

which is true about a beta particle a. it has same mass as a helium nucleus b. when ejected from the nucleus formed has same mass as original isotope c. when ejected from nucleus of a radioisotope, the nucleus formed has one more proton d. it is the same as gamma radiation

c. when ejected from nucleus of a radioisotope, the nucleus formed has one more proton

the element that is essential for human nutrition and is responsible for formation of bones and teeth is ___

calcium

a sample of magnesium weights 10 grams. how many moles are there a. 10 moles b. 6 * 10^23 moles c. 60 *10^23 atoms d. 0.4 moles

d. 0.4 moles

how many protons and electrons does Mg 2+ have a. 12 protons, 12 electrons b. 12 protons, 12 electrons c. 14 protons, 12 electrons d. 12 protons, 10 electrons

d. 12 protons, 10 electrons

scandium-404 enters into a reaction in which a positron is emitted. which is the correct equation for this reaction a. 40 sc -> 34 sc + 0B+ 21 21 1 b. 40 sc -> 36 sc + 0B+ 21 21 1 c. 40 sc -> 36 sc + 0B+ 21 20 1 d. 40 sc -> 40 sc + 0B+ 21 20 1`

d. 40 sc -> 40 sc + 0B+ 21 20 1

what is the molar mass of ammonium oxide a. 30.00 g/mol b. 34.00 g/mol c. 44.00 g/mol d. 52.00 g/mol

d. 52.00 g/mol

nitrogen can have an anion, N 3-. this ion a. is result of the atom gaining three electrons b. can form three ionic bonds c. has eight electrons in the outside orbit d. all the above

d. all the above

the atoms structure characteristically has a. protons and neutrons within the nucleus b. electrons located outside the nucleus c. mostly empty space d. all the above

d. all the above

the name for the cu 2+ ion is a. copper ion b. cobalt (II) ion c. copper (I) ion d. copper (II) ion

d. copper (II) ion

proper name of the compound N2O3 a. nitrate b. nitrogen (II) oxide c. nitrogen trioxide d. dinitrogen trioxide

d. dinitrogen trioxide

NO3 - is the ___ ion a. nitrous b. nitrogen trioxide c. nitrite d. nitrate

d. nitrate

the formation of ions typically occurs when a. nonmetal atoms lose electrons and metals gain them b. metal and nonmetal atoms are close together in number of valence electrons c. metal and nonmetal atoms have same number of electrons d. nonmetal atoms gain electrons and metal atoms lose them

d. nonmetal atoms gain electrons and metal atoms lose them

atoms of elements belonging to the same group have an identical number of a. total electrons b. energy levels c. inner electrons d. valence electrons

d. valence electrons

calculate the number of moles in 2.61 grams of silicon

.0929 moles

how many moles are in 25.00 g of water

1.389 moles

complete the equation. 239 pu + 1 n -> 104 mo + 2n + ___ 94 0 42 0

134 Te 52

proper notation for the oxygen isotope with atomic number 8 and mass number of 16

16 O 8

12.5 grams of gold contains how many gold atoms

3.82 * 10^22 atoms

technetium-99 is injected into a patient in order to monitor heart function. technetium-99 is a gamma emitter with half-life of 6 hours. a patient receives an injection of 21 mg of technetium-99 on a tuesday at 9 am. calculate the number of hours and the number of half lives that occur between 9 am on tuesday and 11 pm on wednesday

38 hours, 6.3 half lives

calculate the number of atoms in 2.61 grams of silicon

5.59 * 10^22 atoms

draw a structure expected from the combination of nitrogen and 3 chlorine atoms

Cl Cl:N:Cl