HELP agaIN aSAPPPP!!!!!

Which one of the following statements is correct? A. A pure substance may be separated by filtration or distillation into two or

torisob [31]

Answer: Option (D) is the correct answer.

Explanation:

A pure substance is defined as the substance that is made up of only one type of atom or only one type of molecule.

For example, $Cl_{2}$ is a molecule and it is a pure substance.

Also, substances that contain two or more different element which are chemically combined in a fixed ratio by mass are known as compounds. They are also pure substances.

A pure substance can only be separated by a chemical method and not by any physical method.

A heterogeneous mixture is defined as the mixture which contains non-uniform composition of solute particles into the solution.

For example, mud dissolved in water.

It is not necessary that two or more substance present in a heterogeneous mixture should be of same phase.

Also, it is not necessary that combination of a liquid and a solid always results in a heterogeneous mixture.

If the solid is able to dissolve completely into the liquid then it will result in a homogeneous mixture.

Whereas a homogeneous mixture is defined as the mixture which contains uniform distribution of solute particles into the solvent.

For example, salt dissolved in water is a homogeneous mixture.

Thus, we can conclude that the statement composition is uniform throughout a homogeneous mixture, is correct.

4 0

3 years ago

The salt NaC2H3O2 would form from the combination of:

Nuetrik [128]

B sodium chloride and nitric acid

4 0

3 years ago

Which reaction will most likely take place based on the activity series? Li > K Ba CaNa > Mn > Zn > Cr> Fe> Cd

allsm [11]

Answer:

Among the given reactions,

a. Ag+FeCl 3

b, Zn + CaO

C. Ba+Na 2 CO 3

d . Cr+KNO3

which reaction is likely to take place based on the reactivity series?

Explanation:

The metal reactivity series is:

Li > K> Ba >Ca>Na > Mn > Zn > Cr> Fe> Cd Ni > H > Sb > Cu > Ag > Pd > Hg > Pt

The highly reactive metal will displace the less reactive metal from its compound during a displacement reaction.

a. Ag+FeCl 3

Ag is less reactive than Fe, so Ag cannot displace Fe from its compound.

This reaction also does not occur.

b, Zn + CaO

Zn is less reactive than Ca, so it cannot displace Ca from its compound.

This reaction does not occur.

C. Ba+Na 2 CO 3

Ba is more reactive than Na, so Ba displaces Na from its compound.

This reaction is possible.

d . Cr+KNO3

Cr is less reactive than K, so it cannot displace K from its compound.

Hence, This reaction is not possible.

Answer:

option c) Ba+Na 2 CO 3 -> BaCO3 +2Na

5 0

3 years ago

The vapor pressure of substance X is 100. mm Hg at 1080.°C. The vapor pressure of substance X increases to 600. mm Hg at 1220.°C

artcher [175]

Explanation:

The given data is as follows.

$P_{1}$ = 100 mm Hg or $\frac{100}{760}atm$ = 0.13157 atm

$T_{1}$ = $1080 ^{o}C$ = (1080 + 273) K = 1357 K

$T_{2}$ = $1220 ^{o}C$ = (1220 + 273) K = 1493 K

$P_{2}$ = 600 mm Hg or $\frac{600}{760}atm$ = 0.7895 atm

R = 8.314 J/K mol

According to Clasius-Clapeyron equation,

$log(\frac{P_{2}}{P_{1}}) = \frac{\Delta H_{vap}}{2.303R}[\frac{1}{T_{1}} - \frac{1}{T_{2}}$

$log(\frac{0.7895}{0.13157}) = \frac{\Delta H_{vap}}{2.303 \times 8.314 J/mol K}[\frac{1}{1357 K} - \frac{1}{1493 K}]$

$log (6) = \frac{\Delta H_{vap}}{19.147}[\frac{(1493 - 1357) K}{1493 K \times 1357 K}]$

0.77815 = $\frac{\Delta H_{vap}}{19.147J/K mol} \times 6.713 \times 10^{-5} K$

$\Delta H_{vap}$ = $2.219 \times 10^{5}$ J/mol

= $2.219 \times 10^{5}J/mol \times 10^{-3}\frac{kJ}{1 J}$

= 221.9 kJ/mol

Thus, we can conclude that molar heat of vaporization of substance X is 221.9 kJ/mol.

4 0

2 years ago

What substance takes part in an enzymatic reaction, but is unchanged by the reaction?

Ierofanga [76]

The answer to this question would be: enzyme

<span>Enzyme is a kind of catalyst that </span>will take part in the chemical reaction but it won't be reacted. E<span>nzyme </span>only helps by reducing the energy needed to start the reaction.
Theoretically, the enzyme is not mandatory needed but if you have an enzyme the reaction will be easier, thus increasing reaction speed. But in most case, the reaction might be too slow without enzyme, making enzyme vital in living organism.

5 0

3 years ago