Haven't done real science in a while (studied computer science in college), but I'll give it a shot. I hope you actually want to learn the concepts a little bit (if you just wanted the answer, you could probably have googled the questions), so I'll explain a little bit when I can.
*B compound (see 5)
B) mixture (see 5, basically, anything that is expressed as a chemical formula is a compound; in this case this is the formula for Stannous fluoride, a compound of tin (Sn) and fluorine (F).)
*B) mixture : the gases in air don't react with each other normally, so it's a mixture
Compounds and Molecules 2
Predict which molecules have a greater attraction for each other; C3H8O2 in liquid rubbing alcohol or CH4 molecules in methane gas.
A) C3H8O2 because they are farther apart and moving slower in a liquid.
* B) C3H8O2 because they are closer together and moving slower in a liquid. :
the level of attraction among molecules go like this : solid > liquid > gas
C) CH4 because they are farther apart and moving quicker in a gas.
D) CH4 because they are closer together and moving quicker in a gas.
Compounds are different from mixtures because
*A) compounds are held together by chemical bonds.
B) each original substance in a compound remains chemically unchanged.
C) each substance in a compound maintains its own properties.
D) mixtures are held together by chemical bonds.
The type of bond that forms between metals and non metals on the periodic table. This requires that one of the elements lose electron(s).
*A) ionic bond: An ion is formed when an atom of an element loses one or more electrons (and other gains one or more electrons), hence the name
B) covalent bond
C) metallic bond
Which of the following best explains why aluminum foil will conduct electricity?
A) The metallic bonds are broken
B) It has a full outer shell of electrons that are stable.
* C) It is a metal and its valence electrons are free to move
Which substance has ionic bonds?
A) CO2 : covalent bonds
B) O2 : covalent bonds
* C) CO : this one that actually has both covalent and ionic bonds, called coordinate covalent bond (I think)
The number of valence electrons in aluminum.
*C) 3e- : The atomic number of Aluminum is 13, so the number of electrons in successive orbits is 2, 8, 3 (valence electrons (generally) = number of electrons in outermost shell)
The type of bond in which there is an equal sharing of electrons.
* A) non-polar covalent bond
B) ionic bond
C) polar covalent bond
Which of the depicts the proper ground state electron configuration for K?
I can't explain this without diagrams, but Wikipedia will help: look for "atomic orbital" and "Hund's rule"
* B) 1s22s22p63s23p64s1 : one thing you can do is count the number of electrons: 2 + 2 + 6 + 2 + 6 + 1 = 19, which is the atomic number of K, i.e. the number of electrons in ground state
Which of the following best describes the noble gases.
A) readily bond with other elements
B) are very unstable
* C) have a full outer shell e.g. Argon, Xenon, Krypton
D) form covalent bonds
Compound Names and Formulas
The empirical formula for glucose is
* A) C6H12O6 : all sugars (glucose, dextrose, sucrose etc.) have chains of carbons; glucose is the one with a straight chain of 6 carbon atoms
Which of the following help to explain why metals rather than ionic solids are used in electrical wiring.
* A) As a solid metal can carry an electric current. : kind of self-explanatory?
B) In metallic bonds charges are held in place when it is solid, while ionic solids allow charges to move freely.
C) Ionic bonds are not flexible, while metal can be bent and stretched because metallic bonds are flexible.
D) Ionic solids hold charges in place and do not allow them to move freely.
Determine the chemical formula for the following ionic compound: strontium nitrate; an ingredient in some fireworks, signal flares, and matches.
* C) Sr(NO3)2 : Have you learned how to write compound formulas? I don't want to explain in too much detail, but basically, Nitrate is an ion of which the formula is NO3, and it has a valency of 1. Sr is a metal and has a valency of 2. Exchange the valencies, and write the positive ion (metal) first.
What is the name of the following covalent compound: N2O
* B) nitrous oxide : I don't know how you would know this without actually learning about this compound: look for it in Wikipedia. By the way, this compound is laughing gas.
C) dinitrogen monoxide
D) trinitrogen dioxide
The ion name and symbol for a Fluorine anion is
A) Fluorinate, Fl
* B) Fluoride, F-
C) Flouride, F
D) Fluoridium, F
What is the ionic formula for magnesium bromide?
* C) MgBr2 : Use technique from 16.
A substance in a solid at room temperature. It is unable to conduct electricity as a solid but can conduct electricity as a liquid. This compound melts at 755 oC. Would you expect this compound to have ionic bonds, metallic bonds, or covalent bonds?
I'm not too sure about this one, but I would guess covalent bond. I know for sure it's not A, because metallic ions are what make metals conduct electricity as a solid.
A) metallic bonds
B) ionic bonds
* (?) C) covalent bonds
In addition to carbon and hydrogen atoms choose another element from the list that can bond with carbon in organic compounds.
* D) nitrogen : Think of amino acids, the building blocks of life
well srry i cannot answer your question