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April, 2025

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NS Show your CHEM knowledge

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Crack.
Posts: 6020 - Karma: 84
aight so it's 11:48 and i'm taking a take home chem test. Got a couple of questions that I can't figure out. Can you guys help me out? Note O are NOT zeroes. And l are not ones. its an EL.

1. Given the incomplete equation: 2N2O5(g)-->?

which set of productss completes and balances the incomplete equation?
1)2N2(g)+2O2(g)
2)2N2(g)+3H2(g)
3)4NO(g)+5O2(g)
4)4NO2(g)+O2(g)

8. According to the activity series chemistry reference table, which pair of substances would undergo a single replacement reaction?

1)F2 and CaCl2
2)Cl2 and CaF2
3)I2 and CaF2
4)I2 and CaCl2

10. when the equation __Na(s)+ __H2O(L)--->__NaOH(aq)+ __H2(g)

1) 1
2) 2
3) 3
4) 4

And last but not least...

11. When C3H8 burns completely in an axcess of oxygen, the products formed are..

1)CO2 and H2O
2)CO and H2
3)CO2 and H2
4)CO and H2O


Well hopefully you guys can help me out. If anyone like freezed or anyone who actually knows this shit well can verify the answers given it would be great! thanks for helping pass chem NS.
16 years ago
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Hansel.
Posts: 4583 - Karma: 112
i believe #8 is c
and #11 is a
16 years ago
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comeatmebro
Posts: 10720 - Karma: 66
fuck i can't remember any of this man...
16 years ago
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steezeaholic.
Posts: 894 - Karma: 39
i dont  know what numbers are like subscripted
16 years ago
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chapz
Posts: 10182 - Karma: 66
1. Given the incomplete equation: 2N2O5(g)-->?

which set of productss completes and balances the incomplete equation?
1)2N2(g)+2O2(g)
2)2N2(g)+3H2(g)
3)4NO(g)+5O2(g)
4)4NO2(g)+O2(g)

ANSWER: 4 -> (4NO2 + O2)

8. According to the activity series chemistry reference table, which pair of substances would undergo a single replacement reaction?

1)F2 and CaCl2
2)Cl2 and CaF2
3)I2 and CaF2
4)I2 and CaCl2

I DONT KNOW

10. when the equation __Na(s)+ __H2O(L)--->__NaOH(aq)+ __H2(g)

1) 1
2) 2
3) 3
4) 4

ANSWER: 2-> _2_Na(s)+ _2_H2O(L)--->_2_NaOH(aq)+ _2_H2(g)

And last but not least...

11. When C3H8 burns completely in an excess of oxygen, the products formed are..

1)CO2 and H2O
2)CO and H2
3)CO2 and H2
4)CO and H2O

ANSWER: 1
C3H8 + 5O2 --> 3CO2 + 4H2O
16 years ago
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Crack.
Posts: 6020 - Karma: 84
how sure are you about those 3
16 years ago
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chapz
Posts: 10182 - Karma: 66
im almost positive. in the last one, its just like the engine of a car, which is always h2o and co2... for the first one, i just took the charge of the unfinished one which is -32, so then i found the charge of 1 to 4, and 4 came out as-32.. and for the third one, its just not balanced.. so, if you put a 2, the whole equation balances... wait til someone else does it, and if they get the same answers, youre in business haha. but im pretty sure theyre right. what chem are you taking?
16 years ago
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freezed
Posts: 12973 - Karma: 500
1. 4, just gotta balance N and O separately.

8. 1..F can replace CL can replace Br can replace I

10. this question doesn't make sense, did you type the whole thing?

11. 1, CO2 and H2O are the products of complete combustion
16 years ago
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Crack.
Posts: 6020 - Karma: 84
ah crap take that balance it and the question is..when the equation is correctly balanced using the smallest whole numbers, the coefficent of the water is?
16 years ago
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Crack.
Posts: 6020 - Karma: 84
im pretty sure it's 2 but I just want to verify these because theres no reason a take home test shouldn't be a 100
16 years ago
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chapz
Posts: 10182 - Karma: 66
shit its true. putting a 2 in the third question wont balance... and freezed is right, the question doesnt make sense. do you have to use a different number for each blank? or what?
16 years ago
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Crack.
Posts: 6020 - Karma: 84
nah shit it's not 2...that is hardd
16 years ago
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freezed
Posts: 12973 - Karma: 500
the equation balances:

_2_Na(s)+ _2_H2O(L)--->_2_NaOH(aq)+ _1_H2(g)
16 years ago
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freezed
Posts: 12973 - Karma: 500
so the answer is 2, but not for the reason chapz posted earlier, its because it balances like i just posted
16 years ago
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chapz
Posts: 10182 - Karma: 66
well thats what i was thinking.. thats correct, unless they all have to be the same coefficient, which seems impossible. so yeah, thats is correctly balanced.
16 years ago
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Crack.
Posts: 6020 - Karma: 84
so it is 2..haha man I could not get that for some reason. I was trying to get the hydrogen to equal 6. Anyways thanks to freezed and chapz, you guys helped. now I have to do this stuff that will take hours I gotta..

a) predict the products of the double displacement reaction
b) balance the reaction
c) determine the precipitate
d) write the net ionic equations for the reaction

10 of these and i'm done. Thanks again guys.

16 years ago
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freezed
Posts: 12973 - Karma: 500
not too hard, just be systematic and remember the solubility rules.
16 years ago
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Mooose...
Posts: 1807 - Karma: 77
Im backing freezed.

but honestly, make sure you study this shit. its critical to higher level chem courses you could quite possibly be taking in the future.
16 years ago
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Crack.
Posts: 6020 - Karma: 84
So it's probably a bad thing if I don't really understand this stuff?
16 years ago
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chapz
Posts: 10182 - Karma: 66
well, its pretty important... like, the solubility rules are key, unless you have a solubility chart... but the chem im taking now, its general chem, so were learning about everything, so you need to know the stuff youre doing now to be able to go further... what dont you understand?
16 years ago
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summersover
Posts: 5777 - Karma: 233
derek pwning teh chem noobz
maybe if i had passed this course i could help out...
16 years ago
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