If your question is part of your homework, please use this tag. It signifies that instead of a direct answer, care should be taken to explaining the steps to the solution, preferably sticking to just giving helpful, conceptual hints. This tag may be applied to questions which are not homework but ...

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1answer
45 views

Molecular geometry Question about angles

I'm doing this homework and I got: 109.5,109.5,109.5 for D. But it says it is wrong. I don't know why. Can someone help me? Everything else I got right
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0answers
14 views

Heat capacity and finding Delta T? [on hold]

When a reaction was carried out in a bomb calorimeter 2.710 kJ of heat was released. If the initial temperature was 19.897 °C and the total heat capacity of the system was 989.0 J / °C, what is the ...
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1answer
17 views

how will the pressure of a gas in manometer change if it goes to a place with higher pressure

Imagine a manometer where air pressure is 0.8 atm and the gs pressure is more. We move it to sea level which the air pressure is 1 atm. How the gas pressure changes? (the temperature is constant)
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1answer
25 views

Explain why the acidification of solution can lead to separation of ions such as Fe2+ and Zn2+ from aq solution

Given the $K_{sp}(\ce{ZnS})= 2.5\cdot10^{-22}$ and the $K_{sp}(\ce{FeS})= 3.7\cdot10^{-19}$, why would $\ce{Fe^{2+}}$ ions remain in the solution but not $\ce{Zn^{2+}}$ with the acidification of the ...
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1answer
69 views

What are some good research topics for a high school student?

I absolutely love chemistry and I really want to take part in science fairs. I am also taking an AP chemistry class. Cleaner fuel and energy sources and air pollution (especially due to smog and ...
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0answers
32 views

Calculation of Equilibrium Constant

How do You solve this? $$\ce{2SO2 + O2 -> 2SO3}$$ Starting with $1$ mol of $\ce{SO2}$ and $1$ mol of $\ce{O2}$ in a 1 litre flask, the equilibrium mixture required $0.4$ mol $\ce{MnO4^-}$ in ...
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votes
1answer
28 views

How to identify a substance acting as an acid

For question ii, it asks to state a reaction showing $\ce{H2SO4}$ acid acting as an acid. What does it mean acting as an acid? Donating a proton? Very confused as to what to look for. The answer ...
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1answer
23 views

Laws of Chemical Combination

I'm doing revision questions and want to double check something. The opening information reads: Two chlorides of iron were prepared. One was prepared by reacting iron with dry chlorine gas. 4.50 g ...
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2answers
37 views

Chemical Equation: Sulfuric acid and powdered sodium carbonate

Asked to write a balanced chemical equation for the reaction between sulfuric acid and sodium carbonate. The balanced equation isn't the problem. The question asks to also show all the state symbols. ...
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0answers
26 views

A 200g sample of aluminum loses 500 calories [on hold]

A 200g sample of aluminum loses 500 calories. If it starts out at 120 degrees C, find its final temperature (C = .21 cal/gdegreeC)
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1answer
34 views

Degenerated Orbitals

How do I find if an atom has degenerated orbitals? My Understanding I understand that degenerated orbitals mean orbitals that have the same energy level for the same n. However, how do I distinguish ...
0
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0answers
39 views

Michael addition reaction question [on hold]

Under basic conditions, a michael addition reaction can be used to convert compound A into compound B. Show mechanism and reagents used. Explain why no Robinson annelation reaction can occur. ...
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0answers
29 views

Cross Claisen Condensation question [on hold]

The cross claisen condensation of ketone A with compound B creates a 1,3-dicarbonyl compound C. Draw the mechanism for the reaction. State what property of compound B makes it ideal for this type of ...
0
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1answer
32 views

Malonic ester synthesis question [on hold]

How can the malonic ester synthesis be used to prepare carboxylic acid A from the starting material B? Show mechanism and reagents used. Carboxylic Acid A Starting Material B
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1answer
26 views

Empirical and Molecular formula: Homework

I'm working on a high school chemistry book and want to double check one of the homework assignments. The question is for students to write the empirical and molecular formula for 1,2-dichloroethane. ...
0
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1answer
24 views

Difference between an absorbance, emission, and excitation spectrum for uv-visible spectroscopy

The exam paper answer is 500, because we need the wavelength of "maximum absorbance." But this graph shows two curves, and the absorbance curve is omitted. But what is the difference between an ...
0
votes
1answer
53 views

Preparation of a benzoate buffer [on hold]

What mass of sodium benzoate should be added to 140.0mL of a 0.17M benzoic acid solution in order to obtain a buffer with a pH of 4.25? To find mass you need mols i believe and to find mols you need ...
0
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3answers
29 views

pH and materials selction

I working on the Navy study guide for their nuclear engineering programs and I am not a Chemist. Thus, I have come here to try and develop a better understanding of the subject matter. I am trying ...
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2answers
73 views

Given the volumes: determine the pH and the final temperature of a mixture knowing only the initial pH and the temperature of the un-mixed components

I have a pretty basic question but the last time I took Chemistry was in 2007. I am studying the Navy's Nuclear study guide for their interviews and one of the question I am faced with is below. ...
0
votes
1answer
16 views

Calculating molar conductance?

Ok, so the following question is given in my text book. Of the molar conductance value of $Ca^{2+}$ and $Cl^-$ at infinite dilution are respectively $118.88\times10^{-4}$ and $77.33\times10^{-4}$ ...
0
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0answers
27 views

How to calculate m/e value for the base peak in mass spectroscopy?

My working out: Propan-1-ol : CH3CH2CH2OH This can be broken up into: CH3 + CH2CH2OH CH3CH2 + CH2OH CH3CH2CH2 + OH Base peak = most abundant fragment formed (highest peak) How do i know which ...
0
votes
1answer
25 views

UV-Visible Spectroscopy in the analysis of sodium chloride in potato chips

Here is the question and answer out of an exam paper: Firstly, I thought UV-Visible can also use radiation in the visible spectrum. Also when analyzing sodium chloride (a molecule), then UV-Visible ...
0
votes
2answers
36 views

1H-NMR and deducing structures

here is the data booklet we must refer too: Here is the exam paper solution: I dont understand how they conclude this. Peak areas and the chemical shifts seem to be different for me. For ...
1
vote
1answer
23 views

Crystal Field Theory diagram

I need to draw a simple crystal field splitting diagram and identify the lowest-energy spin-allowed ligand field band in the electronic absorption spectrum for [MnCl6]2-. I know the basics of the ...
1
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2answers
45 views

What is a simple ratio in which atoms combine?

According to ModernAtomicTheory :- The ratio in which the different atoms combine may be fixed and integral but may not always be simple. The example given is that in sugar molecule the ratio of C ...
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1answer
20 views

Concentrations of dNTPs

DNA Polymerase III has a Km of 10 micro moles for each of its four substrates (dATP, dCTP, dTTP and dGTP, or dNTCPs for short). During replication, Poll III adds, on average, 750 dNTCPs/sec to each ...
2
votes
1answer
68 views

Identifying 5 unknown substances

Please help me identify the following 5 substances; G, Y, T, L and J G is a white solid which is insoluble in water. Consider the following reactions carried out on solid G. Step 1: Excess dilute ...
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1answer
31 views
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0answers
17 views

A(g) +2B(g) double head arrow C(g) + heat [closed]

The initial concentration of A is 1.0 mole/liter. At equilibrium the concentration of C is 0.50 mole/liter What is the concentration of A at equilibrium in moles per liter?
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0answers
30 views

Simple concentration problem [closed]

I need to know: What is the concentration of a $\ce{100mL}$ sodium sulfate solution diluted to a $\ce{300mL}$ $6.00M$ solution? I think this problem uses $M_1V_1 = M_2V_2$? How is this problem ...
0
votes
3answers
42 views

How does equilibrium change when the products are solid and gas?

$$\ce{CaCO3(s) <=> CaO(s) + CO2(g)}$$ How will the amount of each element change if the pressure is increased? My guess is that the equilibrium will shift to the left, because the right side ...
0
votes
0answers
55 views

Standard enthalpy of formation (KNO3)

Working on a study guide. I'm a little confused by this question, perhaps my understanding of enthalpy isn't as good as it should be. for the compound $\ce{KNO3}$, which of the following reaction ...
1
vote
3answers
57 views

Reaction at Alpha Carbon?

I'm having trouble with the products of these reactions below... I feel like I'm on the right track but don't know why it comes up wrong Figured out the aldehyde - but not the ester one!
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1answer
48 views

Which salt precipitates from a solution of ammonium oxalate and silver nitrate?

I am supposed to write the precipitation reaction for $\ce{(NH4)2C2O4 + AgNO3 ->[\ce{H2O}]}$ Is my equation correct? I left out the Spector ions. $$\ce{4(NH4) + 2 C2 +O4\rightarrow 4(NH4)2CO3}$$
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1answer
36 views

Indonesian Chemical Olympiad: Searching mass of barium peroxide

(This problem is taken from Indonesian Chemical Olympiad) A sample contain barium peroxide added to a glass full of sulfuric acid. It produce insoluble product and its filtrate. The filtrate is ...
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1answer
46 views

How many milliliters of 0.202M NaOH to 25.ml of 0.0233M salicylic acid to adjust the pH to 3.5

I'm studying for exam tomorrow and ran into another question that i'm having trouble with. This one seems easy but I am not getting the right answer. How many milliliters of $0.202$ M NaOH should ...
1
vote
1answer
64 views

Using Activities and extended Debye-Huckel equation, find the ph of the solution 0.020 M NaCl

This is from a study guide for an exam coming up. So the Question is: Use activities to calculate the pH of each of the following solutions, being sure to use $\alpha$ values and the extended ...
2
votes
1answer
58 views

Ratio of conjugate bases of a tricarboxylic acid

Hi does anyone know how to solve this question? A tricarboxylic acid $\ce{H3A}$ has three different types of $\text{p}K_\text{a}$ $(\text{p}K_\text{a, 1} =2.0,$ $\text{p}K_\text{a, 2}=5.0,$ ...
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votes
1answer
26 views

Balance equation and percent yield? [closed]

Some of the acid in acid rain is produced by reacting nitrogen dioxide with water. The products of this reaction are nitrogen monoxide and nitric acid, $\ce{HNO3}$. A raindrop weighing 0.05 g comes ...
1
vote
1answer
53 views

Best solvent for crystallization + mass recovered from crystallization + purity of the product

I have a chemistry final tomorrow and this question on my sample exam through me for a loop. I'm not entirely confident I can work out problems B and C, but those questions rely on the answer to A. ...
0
votes
1answer
22 views

qualitative permanganate test on sodium peroxoborate [closed]

what is the balanced equation between sodium peroxoborate, potassium permanganate and sulfuric acid in the qualitative permanganate test done on sodium peroxoborate. why is this test done?
1
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1answer
41 views

Can an excessive reactant amount result in a longer reaction time?

I am performing an experiment with DTZA and Ferrate. After a point of increasing the DTZA concentration too much the Ferrate takes longer (lower reaction rate) to react with the DTZA. Is this ...
1
vote
1answer
35 views

Titration of ferrous oxalate with potassium permanganate

Number of moles of $\ce{MnO_4^-}$ required to oxidize one mole of ferrous oxalate completely in acid medium will be: (a) 7.5 moles (b) 0.2 moles (c) 0.6 moles (d) 0.4 moles In ...
1
vote
1answer
169 views

Calculate the moles of acid and conjugate base needed

I tried to look up the way to do this question but I could not find any helpful information in order to help me solve this question. Q: Using the following salts listed below, calculate the moles of ...
2
votes
1answer
31 views

Volume required to dilute solution for a pH change

A 100 ml solution of NaOH has a pH of 13. What volume of water, in mL must be added to change the pH to 11? My Steps: So, begin by calculating conc. of [OH-] for pH 13. Then find the moles by ...
1
vote
1answer
36 views

Concentration from Absorbance vs Time

I am given a protein, BAPNA, and the initial concentration of the protein. The experiment involves reaction rates of varying protein concentrations. Each sample cuvette is inserted into a ...
5
votes
1answer
50 views

Electrochemistry Question from USNCO

Given these standard reduction potentials, what is the standard reduction potential for $$ \ce{Co^{3+}(aq) +3e- -> Co(s)} $$ Given: $$ \ce{Co^{3+}(aq) + e- -> Co^{2+}(aq)} \ \ \ E°=1.82 V ...
2
votes
2answers
33 views

The effect of concentration on the rate of a homogenous reaction

I have to do an experiment where I will find out what the influence of the concentration on the reactionspeed of a homogenous reaction is. We are asked to create 2 solutions, respectively A and B: ...
2
votes
2answers
114 views

Conversion of an amide to an imine

We haven't learned this in class yet, but after looking online, and through my textbook, I can't seem to find a definite answer. I am hopelessly and utterly lost.
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1answer
39 views

Cleavage of an amide under acidic conditions

I think I'm doing it correctly but perhaps I'm missing something? Do they both need to be protonated