Chemistry questions that I don't get please help?

I know this is a lot but I did the whole entire test and I don't know these ones and there nowhere to be found on the internet!!! Please help meee

1. Which quantity represents 0.500 mole at STP?

a) 32.0 grams of oxygen

b) 28.0 grams of nitrogen

c) 11.2 liters of oxygen

d) 22.4 liters of nitrogen

2. How many moles of hydrogen atoms are there in one mole of C6H12O6 molecules?

a) 12

b) 12(6.0 x 10^23) ( I put this one )

c) 24

d) 24(6.0 x 10^23)

3. Which change must result in an increase in the average kinetic energy of teh molecules of a sample of N2 (g)?

a) The density changes from 2.0g/l to 2.5g/l

b) The pressure changes from 0.5 atm to 1 atm

c) The volume changes from 1 liter to 2 liters

d) The temperature changes from 20 Celsius to 30 celcius ( I put this one )

4. Which orbital notation represents the second principal energay level of a silicon atom in the ground state? (BY BOXES I MEAN ORBITALS)

a) one box (filled with 2 electrons) three boxes (filled with 2 electrons in first box)

b) one box (filled with 2 electrons) three boxes (1st box 2 electrons, 2nd box 1 electron, 3rd box 1 electron)

c) one box (filled with 2 electrons) three boxes (1st box 1 electron, 2nd box 1 electron, 3rd box no electrons)

d) one box (filled with 2 electrons) three boxes (all 3 boxes filled with 2 electrons each)

5. Teh pressure on 30 milliliters of an ideal gas increases from 760 torr to 1520 torr at constant temperature. The new volume is

a) 30 x 760/1520

b) 30 x 1520/760

c) 1520/30 x 760

d) 760/30 x 1520

6. The diagrams below represent four 500-mililiter flasks. Each flask contains the gas represented by its symbol. All gas samples are at STP. Ne, Ar, H2, CO2. Each flask contains the same number of?

a) molecules, only

b) atoms, only

c) atoms, but different numbers of molecules

d) atoms and molecules

7. Elements whose two outermost sublevels may be involved in a chemical reaction are called

a) noble gases

b) alkali metals

c) halogens

d) transition metals

8. A gas volume that contains an equal number of hydfrogen and oxygen molecules has a pressure of 0.6 atmosphere. The partial pressure due to the oxygen molecules is

a) 0.1 atm

b) 0.6 atm

c) 0.3 atm

d.) 0.2 atm

9. At STP, 25.0 liters of a gas has a mass of 50.0 grams. What is the gram molecular mass of the gas?

a) 11.2 g

b) 25.0 g

c) 44.8 g

d) 75.0 g

10. Helium may be liquefied at low temperature and high pressure primarily because of

a) van der Waals forces

b) hydrogen bonding

c) covalent bonds

d) ionic attraction

11. If X is the symbol of a noble gas atom in the ground state, its electron-dot symbol coulb be

a) 1 dot

b) 5 dots

c) 2 dots

d) 3 dots

12. The density of a gas is 0.77 gram per liter at STP. What is the formula mass of the gas?

a) 8.5 g

b) 29 g

c) 34 g

d) 17 g

13. Part 2 question. There was an abbreviated Periodic Table of Elements with just letters replacing elemental symbols. It asked to find which had the

highest electronegativity value,

most metallic,

greatest atomic mass,

which is chemically similar to element A,

and the smallest atomic radius.

I got all of those answers but the last one says this...

Explain how you know that none of the elements shown can be a noble gas? I have no idea

1 Answer

  • Anonymous
    9 years ago
    Favorite Answer

    Ask your teacher for help but I have some guidelines to help you:

    1. C - ALL STP gases that are 1 mol have a volume of 22.4 Liters, remember that! So if its .5 mol you half it, 22.4/2 = 11.2 L

    2. I believe you are right!

    3. I believe you are right!

    4. C - If I Read correctly (and assuming since i dont have a periodic table on me) that Si is below Carbon, so the answer is C. Why? Hund's rule...look that up

    5. Since the ideal gas does not involve moles used PV = PV

    6. I think it is A since gasses occupy same volume at STP, but some more/less atoms than others

    7. I think its D because the d orbitals in the transitional metals are almost degenerate from the s shell at the (well since d orbitals are at the previous shell...)'next' level.

    8. Use Dalton's law of partial pressures and set up a proportion

    9. Use M = dRT/P

    10. disperion forces

    11. C- Think of helium

    12. Use the same principle as #9

    13. Hmmm thats odd...noble gases have smallest atomic radius for their period, metallic properties of them increase as one goes down from Helium to ununoctium, and GENERALLY has the greatest atomic mass of the period.

    Hope this helps :)

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