What is a molecule made of?provide an example of one .

Predict the Solubility of the following substances in water.

anyanavicka [17]

a. NaNO3: soluble
b. AgBr: insoluble
c. NH4OH: soluble
d. Ag2CO3: insoluble
e. NH4Br: soluble
f. BaSO4: insoluble
g. Pb(OH)2: soluble
h. PbCO3: insoluble

5 0

3 years ago

What are two important benefits of the new material modeled on sharkskin?

frozen [14]

Answer:

Lightweight and wrinkle-free, sharkskin is ideal for curtains, tablecloths and napkins. Sharkskin fabric is popular for both men's and women's worsted suits, light winter jackets and coats. Sharkskin is commonly used as a liner in diving suits and wetsuits.

7 0

3 years ago

If you need to extract a 50 ml aqueous solution with 50 ml of dichloromethane, what is the minimum size of a separatory funnel y

tatuchka [14]

The dichloromethane (DCM) has less density than water and also the polarity of water is much more than DCM. So the mixture of water and dichloromethane will always be a heterogeneous mixture. In the mixture dichloromethane will be always up of the water layer. The volume of the separatory funnel which contains the mixture of DCM and water must have to be more than the total volume of the liquids thus the volume of the funnel will be more than (50+50) = 100mL.

The caution have to consider during the separation are-

1. The separatory funnel have to shake well with lid and have to settle down for some times until the two liquid separated.

2. The lid should be open very slowly as the vapor pressure of DCM is more and it will float on the water.

3. After this the stopcock should be opened and slowly the water will come out first followed by DCM.

7 0

3 years ago

H2(g) + F2(g)2HF(g) Using standard thermodynamic data at 298K, calculate the entropy change for the surroundings when 2.20 moles

abruzzese [7]

Answer: The value of $\Delta S^o$ for the surrounding when given amount of hydrogen gas is reacted is -31.02 J/K

Explanation:

Entropy change is defined as the difference in entropy of all the product and the reactants each multiplied with their respective number of moles.

The equation used to calculate entropy change is of a reaction is:

$\Delta S^o_{rxn}=\sum [n\times \Delta S^o_{(product)}]-\sum [n\times \Delta S^o_{(reactant)}]$

For the given chemical reaction:

$H_2(g)+F_2(g)\rightarrow 2HF(g)$

The equation for the entropy change of the above reaction is:

$\Delta S^o_{rxn}=[(2\times \Delta S^o_{(HF(g))})]-[(1\times \Delta S^o_{(H_2(g))})+(1\times \Delta S^o_{(F_2(g))})]$

We are given:

$\Delta S^o_{(HF(g))}=173.78J/K.mol\\\Delta S^o_{(H_2)}=130.68J/K.mol\\\Delta S^o_{(F_2)}=202.78J/K.mol$

Putting values in above equation, we get:

$\Delta S^o_{rxn}=[(2\times (173.78))]-[(1\times (130.68))+(1\times (202.78))]\\\\\Delta S^o_{rxn}=14.1J/K$

Entropy change of the surrounding = - (Entropy change of the system) = -(14.1) J/K = -14.1 J/K

We are given:

Moles of hydrogen gas reacted = 2.20 moles

By Stoichiometry of the reaction:

When 1 mole of hydrogen gas is reacted, the entropy change of the surrounding will be -14.1 J/K

So, when 2.20 moles of hydrogen gas is reacted, the entropy change of the surrounding will be = $\frac{-14.1}{1}\times 2.20=-31.02J/K$

Hence, the value of $\Delta S^o$ for the surrounding when given amount of hydrogen gas is reacted is -31.02 J/K

7 0

3 years ago

Is propane, c3h8, an element, a compound, a homogeneous mixture, or a heterogeneous mixture?

julsineya [31]

Pure substances that cannot be broken down into other substances by any chemical or physical means are known as element.

Pure substances that can be broken down into elements by any chemical or physical means are known as compounds.

Combination of pure substances in which they retain their properties is known as mixture.

Mixtures in which the components of mixture are uniformly distributed are known as homogeneous mixture whereas mixtures in which its components are can be easily seen are known as heterogeneous mixture.

Since propane, $C_3H_8$ is made up of two different elements that is carbon, $C$ and hydrogen, $H$ . There are 3 carbon and 8 hydrogen atoms present in the propane molecule.

So, it is a compound.

4 0

3 years ago