If your question is part of your high school or college/university 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 ...

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2answers
45 views

Determining if reaction is endothermic or exothermic using equilbrium constant

For the following reaction: $$W_{(s)}+4\,Br_{(g)}\rightleftharpoons WBr_{4(g)}$$ At 900 K, $K_{p}=100$ and at 2800 K, $K_{p}=5$. At higher temperatures, the equilibrium has shifted towards the ...
0
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1answer
36 views

Density of an object

To complete homework I am working on, I need help finding the density of a penny. I'm not given the mass or the volume. All I know about this penny is it's zinc coated in copper, and I am given the ...
4
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1answer
72 views

Length of copper wire in 1 lb spool

This is a homework question in my Hon. General Chemistry I class. Below this is the question, then below that is my work and answer explained as clearly as I could manage. Question: The diameter of ...
2
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2answers
59 views

Water as a strong Base

Question: Classify each of the following ions according to whether they react with water to give a neutral, acidic, or basic solution: As a general rule: Strong acid + Strong base ...
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1answer
30 views

Analyzying Collection from Evaporation [on hold]

A solution is 5.00% potassium chloride by mass. How much potassium chloride would you expect to collect by evaporating 150.0 g of the solution?
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1answer
65 views

The difference between heat of reaction at constant pressure and that at constant volume

If supposing the kp value of a reaction is 10 Atm at 300K and 4atm at 400K. Then how can we say that the difference between the heat of reaction at constant pressure and that at constant volume is RT ...
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2answers
81 views
+50

Determining equilibrium constant of complex cell(Hard Question)

Question: The following galvanic cell has a potential of 1.214 V at 25 °C: $$Hg_{(l)}|Hg_{2}Br_{2(s)}|Br^-(0.10\,M)||MnO_{4}^-(0.10\,M)|Mn^{2+}(0.10\,M),H^+(0.10\,M)|Pt_{(s)}$$ Calculate the ...
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0answers
16 views

Strategy to determine half-reactions of synthesis and decomposition reactions [closed]

Question: For the following equations, what strategy would be used to determine the two half reactions. \begin{aligned}\ce{ (1) && Mn(OH)_{2(s)} + H_{2}O_{2(aq)} &->T[base] ...
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3answers
74 views

What are the most important resonance structures of 5-aminocycloheaxa-2,4-dienone?

Here attached is a question from my exam. My TA removed 1 point out of 7 for a reason. Can anyone decipher for what? There's the writing in red but it is illegible to me. I don't understand to what he ...
0
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1answer
23 views

Determining the group number of an element from its successive ionization energies

The successive ionization energies of an unknown element X are: 1st - 9534; 2nd - 11790; 3rd - 13683; 4th - 15309; 5th - 16458. To what group number does X belong? There aren't any significant ...
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2answers
27 views

Determining boiling point on a created temperature scale

Quesion 1.Assume that you construct a thermometer using gallium as the fluid instead of mercury, and that you define the melting point of gallium as 0 °G and the boiling point of gallium as 1000 ...
4
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1answer
42 views

Chemical equilibrium-reaction of change in pressure problem

I am having a problem in the following question. Ammonium carbamate dissociates as shown below. $$\ce{NH2COONH4_{(s)} -> 2NH3_{(g)} + CO2_{(g)}}$$ In a closed vessel containing ammonium ...
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1answer
28 views

What is the length of a unit cell of CuCl assuming that it is fcc?

The density of CuCl is given - x gm/cmm The crystal structure is assumed to be fcc. My teacher is claiming the we can apply the formula $$\rho=\frac{Z * M}{a^3 * N_0}$$ And he took M = 35.5+63.5gm = ...
2
votes
3answers
72 views

Which has higher rate of hydrogenation- methyl propene or trans-2-butene?

I know that cis-2-butene has a higher rate of hydrogenation than both of these due to steric reasons, but here both of these compounds have same steric hindrance. So, when they come in contact with ...
2
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1answer
63 views

Why is the equilibrium constant given in litre per mole?

At $800\:\mathrm{K}$ a reaction mixture contained $0.5\:\mathrm{mol}$ of $\ce{SO2}$, $0.12\:\mathrm{mol}$ of $\ce{O2}$ and $5\:\mathrm{mol}$ of $\ce{SO3}$ at equilibrium. $K_c$ for the equilibrium ...
3
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2answers
114 views

AgNO3 + HCl reaction

Consider the reaction of $\ce{AgNO3}$ and $\ce{HCl}$. I read that silver chloride would be formed. But $\ce{H} > \ce{Ag}$ in reactivity, then how could $\ce{Ag}$ displace $\ce{H}$ from $\ce{HCl}$ ? ...
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1answer
63 views

Why is the addition of a singlet carbene to an alkene stereospecific? [closed]

Why is the addition of a singlet carbene to an alkene stereospecific, but not when a triplet carbene is added?
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1answer
34 views

Pectinase enzyme assay

I am working on pectinase enzyme assay. I incubated 900 ul of substrate for 10 minutes in the water bath, followed by adding 2ml of DNSA reagent, then 100ul of enzyme extract added finally i read the ...
1
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1answer
20 views

What does (heated) mean in a chemical equation?

I'm supposed to balance the following equation: $\text{Potassium chlorate (heated) --> Potassium chloride + Oxygen}$ But I don't understand what the (heated) means in front of the first element. ...
0
votes
1answer
31 views

Distinguishing between 'particles', 'molecules' and 'chemical species'?

I have read this article about the difference between 'compound', 'mixture', 'element' and 'molecule', but I would like to know the precise definitions for more terms (see below). From the article, ...
3
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1answer
36 views

Disposing of Hazardous Waste: General

I'm doing a book for the African market and the syllabus asks for discussions on proper disposal of chemicals and waste products, particularly in the classroom setting. The authors said something ...
3
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1answer
39 views

In a mixture of ammonia and hydrogen hypochlorite, how do I determine the oxidising and reducing agent?

$$\ce{NH_3 + HOCl <=> NH_2Cl + H_2O}$$ How do I figure out what the oxidizing agent is and reducing agent? I know that the oxidizing state of $N$ in $\ce{NH_3}$ is $-3$, but I'm not sure how to ...
0
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1answer
21 views

Percentage Yield Question

I apologise for how simple this question is, but I am really struggling with getting to the answer. I have looked online for the answer, but I don't understand where they obtain the 3/2 in: From ...
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1answer
11 views

Calorimetry | Heat produced VS Change of enthalpy

There are two questions on the same test paper. Calculate the amount of heat energy, $q$, produced in the reaction Find the change of heat ($-q$). I'm not sure whether or not they mean the same ...
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2answers
20 views

How can I find the heat that will be released in kJ per gram for the reaction of Al with Fe2O3?

Find the heat that will be released in kJ per gram when aluminium ($\ce{Al}$) reacts with $\ce{Fe2O3}$ as follows : $\ce{2Al(s) + Fe2O3(s) → Al2O3(s) + 2Fe(l)}$ the information given is: $\Delta H ...
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0answers
23 views

∆Enthalpy of diatomic molecules

Question: The reaction between hydrogen and oxygen to yield water vapor has $\Delta{}H^\circ = -484~\mathrm{kJ}$. How much $PV$ work is done, and what is the value of $\Delta{}E$ in kilojoules ...
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2answers
383 views

Which compound has the highest melting point?

Which of the following compounds has the highest melting point : $\ce{PCl5}$, $\ce{H2O}$, $\ce{NaCl}$, $\ce{SrCl2}$, $\ce{CaF2}$? I've asked a question concerning the boiling points and I got an ...
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2answers
53 views

How can I get a hand sanitizer solution to form a gel?

I am trying to formulate a gel hand sanitizer for a thesis project. The sanitizer that I have right now is watery and will not gel. My teacher told me to change our formulation because it is not ...
2
votes
2answers
56 views

Find n and the wavelength too

To start with its a homework problem, quite lengthy. A particle of mass equal to 208 times the mass of electron moves in a circular orbit around a nucleus of charge +3e. Assuming the BOHRs model of ...
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1answer
24 views

Balancing ionic equations and determining number of ions

There were two questions that I've listed below that I've had troubles on. I got an answer in both, but both of them weren't correct. For the first question, they list the answer to be D and then ...
1
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1answer
18 views

Arrange B , Be , Li in order of increasing IE2

IE2 = Second ionization energy the correct arrange of them is like this : Be < B < Li ... But why? Li will have the greatest IE2 because that will involve removing a core electron but what I ...
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1answer
43 views

Subtle implications of quantum numbers

Question: Given the subshells 1s, 2s, 2p, 3s, 3p , and 3d , identify those that meet the following descriptions: a) has l=2 b)Can contain two electrons with spin $m_{s}=\pm\dfrac{1}{2}$. For a) From ...
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1answer
36 views

the oxidation number of N in this equation?

the equation : $\ce{NH4Cl + AgNO3 = NH4NO3 + AgCl}$ I know that oxidation number of $\ce{N}$ in $\ce{NH4Cl}$ is -3 and in $\ce{AgNO3}$ is +5 but what I am confused about is the oxidation number of ...
0
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1answer
21 views

What are the products of the reaction between propanal + H

I'm having trouble figuring out how to figure out the products of this aldehyde and hydrogen reaction? Would it be an oxidation reaction or redox? Any help would be great.
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2answers
68 views

Justify the use of molality and molarity to determine mass. (Hard home-work problem)

An aqueous solution of a certain organic compound has a density of $1.063~\mathrm{g/mL}$, an osmotic pressure of $12.16~\mathrm{atm}$ at $25.0~\mathrm{^\circ{}C}$, and a freezing point of ...
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1answer
39 views

How to study chemistry effectively, quickly and enjoyably [closed]

I'm not sure if this question belongs in the meta section or not, and if it does, do tell me and I'll repost it elsewhere, thanks! Basically, I have 40+ days to my final exam. I've been trying to ...
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1answer
56 views

calculate the amount of energy in KJ necessary to convert 346 g of liquid water from 0 C to water vapor at 182 C

Calculate the amount of energy in $\mathrm{KJ}$ necessary to convert $346~\mathrm{g}$ of liquid water from $0~^\circ\mathrm{C}$ to water vapor at $182~^\circ\mathrm{C}$. The correct answer is ...
0
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1answer
39 views

How do I find out if ions are oxidised/ reduced based on half cell potentials?

I have a question that I keep getting wrong and I need some help on it. Assuming standard conditions, answer the following questions. (yes/no) Is $\ce{Fe^{2+}(aq)}$ capable of reducing ...
5
votes
2answers
447 views

is this statement always true? : The more -OH functional groups in the molecule, the more is its viscosity

Is the following statement always true? The more $\ce{-OH}$ functional groups in the molecule, the more is its viscosity? I think it is true, because it is known that weak intermolecular forces ...
2
votes
1answer
54 views

Electrochemistry question about equilibrium in half cell reaction

Given the following half-reactions: $\ce{Ce^{4+} + e− -> Ce^{3+}}$ E° = 1.72 V $\ce{ Fe^{3+} + e− -> Fe^{2+}}$ E° = 0.771 V A solution is prepared by mixing ...
2
votes
2answers
28 views

Find the color of the solution

The acid-base indicator methyl red has a $K_{a}$ = $1 \times 10^{-5}$. Its acidic form is red while its alkaline form is yellow. If methyl red is added in a colorless solution with a $pH = 7$, the ...
2
votes
3answers
42 views

What is the partial pressure of oxygen in this mixture of oxygen and argon?

A $19.3\:\mathrm{g}$ mixture of oxygen and argon is found to occupy a volume of $16.2\:\mathrm{L}$ when measured at $675.9\:\mathrm{mmHg}$ and $43.4\:\mathrm{^\circ{}C}$. What is the partial ...
0
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1answer
37 views

Equilibrium Graphs

What if I2 and H2 began at the same concentration - then do we start at the same point? ... or is it acceptable to start at different concentrations...
0
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1answer
20 views

Equilibrium Practical Discussion Help

I understand the theory, but am struggling to answer the following discussion questions: (i) Why isn't this represented by: Fe3+ (aq) + 3 SCN- (aq) <-> Fe(SCN)3 (aq) Why do we dilute the ...
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0answers
16 views

Analytic Chemistry question [closed]

On being heated in oxygen 5.72 grams of red metal oxide 'A' was converted to 6.36 grams of black metal oxide 'B'. When 4.77 grams of 'B' was heated in a stream of H2(dihydrogen), 3.81 grams of metal ...
2
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1answer
15 views

A 1.00 L gas at 100. °C and 500. torr contains 70.0 % He and 30.0 % Ne by mass. What is the partial pressure of He?

A $1.00~\mathrm{L}$ gas at $100~^\circ\mathrm{C}$ and $500~\mathrm{torr}$ contains $70.0\%~\ce{He}$ and $30.0\%~\ce{Ne}$ by mass. What is the partial pressure of $\ce{He}$? My answer is ...
3
votes
1answer
62 views

What do the half-reactions need to be for balancing a redox reaction in an acidic medium?

Question: Balance the following reaction: $\ce{CuS + SO4^{2-} -> CuO + SO2}$ My Efforts: Number mentioned in the brackets oxidation number of S I have found out that the oxidation ...
4
votes
5answers
208 views

What is the proper Lewis structure for HCOOH?

I tried to draw the Lewis structure of $\ce{HCOOH}$ but I didn't get the correct representation. As you can see in the picture below, at no. 1, I put $\ce{C}$ as the central atom because it has less ...
7
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1answer
56 views

Does having constant pressure imply a temperature change? Why isn't the volume needed to calculate the final temperature and energy?

Calculate the final temperature and the change in internal energy when $500\:\mathrm{J}$ of energy is transferred as heat to $0.900\:\mathrm{mol}$ $\ce{O2(g)}$ at $298\:\mathrm{K}$ and ...
0
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1answer
34 views

Is Oxygen a Lewis acid?

As I recall a Lewis acid is a substance that can accept an electron pair from a donor substance and oxygen seems to be able to do that for example in $\ce{H2 + O -> H2O}$ so is oxygen a Lewis ...