# Questions tagged [homework]

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### Plot Binary Eutectic from Temperature of Melting and Enthalpy

I'm a little confused about plotting a binary eutectic diagram (temperature vs mole fraction), and finding the eutectic point. I understand the eutectic point is the lowest temperature that a mixture ...
26k views

950 views

### Molarity to Percent, Mole Fraction, Molality

I have a series of questions similar to the following. I want to make sure I do this correct before I do the others. I am in need of a hint. ...
13k views

### When Z>1 are repulsive forces dominant or are attractive forces dominant?

According to PVreal = ZRT If z >1 repulsive forces are dominant or are attractive forces? Different teachers are telling contradictory answers and after referring a few books, I have become more ...
130 views

### How should I construct the orbitals of dilithium using only pen and paper?

For a week I have lessons about quantum chemistry and I have a trouble understanding how to arrive at the good answer for the drawing of the orbital $(\ce{III})$ for $\ce{Li2}$ (see the second picture)...
3k views

### What to do when there is an odd number of valence electrons left on the the central atom?

For example, I'm trying to write the formula for $\ce{NO}$, and $\ce{ClO2}$. The steps my teacher gave me always assume that the central atom has a full valence, or more than full, after the outer ...
136 views

### Finding moles of different compounds using balancing

$$\ce{K2Cr2O7 + x\,H2SO4 + y\,SO2 -> Cr2(SO4)3 + K2SO4 + z\,H2O}$$ For $\ce{Cr}$ change in oxidation number is: $+12$ becomes $+6$ For $\ce{S}$ change in oxidation number is: $+4y$ becomes ...
674 views

### ph & pOH - Autoionization of Water

So I was learning about pH and pOH and it made sense. I looked at strong, weak acids & bases and learned that they dissociate completely in water. So then I moved on to water and learned about the ...
726 views

### Naming rules and acidity of Cl2CHCH2COOH

How do we name $\ce{Cl2CHCH2COOH}$ ? Is seeing branched chain our number 1 priority so we name it 1,1-dichloro-3-propanoic acid? also Which is more acidic $\ce{Cl2CHCOOH}$ or $\ce{Cl2CHCH2COOH}$ ?...
3k views

### Volume change inside a balloon upon decreasing the the outer pressure

A balloon is filled with hydrogen at room temperature. It will burst if pressure exceeds 0.2 bar. If at 1 bar pressure the gas occupies 2.27 L volume, upto what volume can the balloon be expanded? ...
8k views

### Solubility of calcium hydroxide determined by titration

For a lab I had to determine the solubility and $K_{sp}$ of $\ce{Ca(OH)2}$ by performing two different titrations. I am given the formula to find solubility in molarity it is as written below. ...
19k views

### Calculating pH: Weak Acid, Strong Base

This is a question that had me puzzled for quite a while. I feel that information is missing. A weak acid, $\ce{HA}$, $K_a = 1.0$ x $10^{-4}$, is titrated with $\ce{NaOH}$. At the equivalence point,...
669 views

### Precipitation of citric acid by CaCl2 and Ca(OH)2? [closed]

I need to precipitate citric acid from an aqueous solution in the form of calcium citrate. There are, to my knowledge, two different methods of doing this: using $\ce{CaCl2}$ and which will react ...
259 views

### Mathematical form of four hybrid orbitals

The mathematical form of the four $\ce{sp^3}$ hybrid orbitals are given below. \begin{align} \ce{ \tag{a} sp^3 &= 1/2s + 1/2p_x + 1/2p_y + 1/2p_z\\ \tag{b} sp^3 &= 1/2s + 1/2p_x - 1/2p_y - 1/...
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### Why are more electronegative atoms better leaving groups?

My book says, "halide anions are electronegative and can easily stabilise negative charge, hence are good leaving groups." 1) what exactly does "stabilising negative charge" mean? I have read: " ...
1k views

### Equilibrium constants for parallel reactions

So, I am attempting to calculate the equilibrium constant for two separate reactions. A+B<--->C+D and A+B<--->C+E I have figured out the final pressures at equilibrium for A, B, C, D, and E. I ...
11k views

### Is glycerol/glycerin soluble in ethanol?

As titled, I wish to know if glycerol/glycerin is soluble in ethanol (not soluble, slightly soluble, very soluble)
439 views

### Balancing the oxidative decomposition of FeS2

Doing some practice for the GRE next year. Please could you look at my working for this and tell me why I'm wrong? $$\ce{? FeS2 + ? O2 + ? H2O = ? Fe(OH)3 + ? H2SO4}$$ My working so far is: There ...