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3 years ago

2. Why is the salt solution heated

Chemistry

2 answers:

andriy [413]3 years ago

7 0

Answer:

Heating the solution will cause the temperature of the salt solution to increase. By increasing the temperature of the salt solution the rate of evaporation will increae. Evaporation is the change of a substance from a liquid phase to a gaseous phase.

Explanation:

Hope it would be helpful...

stira [4]3 years ago

5 0

When the solution is heated, the water evaporates. ... The salt does not evaporate and so it stays behind. Salt solution is heated.

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Explain why more iron filings are located at the ends of the magnet than at

zvonat [6]

Answer:

Inside the bar magnet, the B is actually stronger at the centre (like in the case of a solenoid). Outside the bar magnet, B is small near the centre since there are very less open field lines there. ... A magnet has attracted iron pieces for many times your welcome XD

Explanation:

6 0

3 years ago

) Calculating Heat from Thermochemical Equations

SIZIF [17.4K]

A combustion reaction is a reaction that reacts in the presence of oxygen molecules. Methane will release -3115 kJ/mol of heat.

<h3>What is a combustion reaction?</h3>

A combustion reaction includes the reaction between the chemical reactant and oxygen molecule to produce the product. The combustion reaction between methane and oxygen is given as:

CH₄(g) + 2O₂ (g) → CO₂(g) + 2H₂O (l), ΔH = -890 kJ/mol

The stoichiometry coefficient from the reaction gives 1 mole of methane releases -890 kJ/mol enthalpy.

So, 3.5 moles methane will release = 3.5 × -890 = -3115 kJ/mol

Therefore, -3115 kJ/mol of heat is released.

Learn more about combustion reaction here:

brainly.com/question/27823881

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4 0

3 years ago

A. property is a characteristic of a pure substance that can be observed without changing the substance into some thing else

wlad13 [49]

The answer is physical property.

Physical properties are the properties that does not require the substance changing into another substance, which is, chemical change. Physical properties are usually observable and measurable, such as melting points, density, odor, color etc. These does not require a chemical reaction to happen.

The opposite of physical property is chemical property, which is how the substance changes to another. Such as how sodium reacts with water to make sodium hydroxide and hydrogen.

7 0

3 years ago

You want to prepare 500.0 mL of 1.000 M KNO3 at 20°C, but the lab (and water) temperature is 24°C at the time of preparation. Ho

timama [110]

Explanation:

As per the given data, at a higher temperature, at $24^{o}C$ , the solution will occupy a larger volume than at $20^{o}C$ .

Since, density is mass divided by volume and it will decrease at higher temperature.

Also, concentration is number of moles divided by volume and it decreases at higher temperature.

At $20^{o}C$ , density of water=0.9982071 g/ml

Therefore, $\frac{concentration}{density}$ will be calculated as follows.

= $\frac{C_{1}}{d_{1}}$

= $\frac{1.000 mol/L}{0.9982071 g/ml}$

= 1.0017961 mol/g

At $24^{o}C$ , density of water = 0.9972995 g/ml

Since, $\frac{concentration}{density}$ = $\frac{C_{2}}{d_{2}}$

= $\frac{C_{2}}{0.9972995}$

Also, $\frac{C_{1}}{d_{1}}$ = $\frac{C_{2}}{d_{2}}$

so, 1.0017961 mol/g = $\frac{C_{2}}{0.9972995}$

$C_{2} = 1.0017961 \times 0.9972995$

= 0.9990907 mol/L

Therefore, in 500 ml, concentration of $KNO_{3}$ present is calculated as follows.

$C_{2}$ = $\frac{concentration}{volume}$

0.9990907 mol/L = $\frac{concentration}{0.5 L}$

concentration = 0.49954537 mol

Hence, mass (m'') = $0.49954537 mol \times 101.1032 g/mol$ = 50.5056 g (as molar mass of $KNO_{3}$ = 101.1032 g/mol).

Any object displaces air, so the apparent mass is somewhat reduced, which requires buoyancy correction.

Hence, using Buoyancy correction as follows,

m = $m''' \times \frac{(1 - \frac{d_{air}}{d_{weights}})}{(1 - \frac{d_{air}}{d})}}$

where, $d_{air}$ = density of air = 0.0012 g/ml

$d_{weight}$ = density of callibration weights = 8.0g/ml

d = density of weighed object

Hence, the true mass will be calculated as follows.

True mass(m) = $50.5056 \times \frac{(1 - \frac{0.0012}{8.0})}{(1 - (\frac{0.0012}{2.109})}$

true mass(m) = 50.5268 g

= 50.53 g (approx)

Thus, we can conclude that 50.53 g apparent mass of $KNO_{3}$ needs to be measured.

8 0

3 years ago

How many protons and neutrons are in the nucleus of isotope with mass of 68.926 amu?

atroni [7]

<span>Isotopes are atoms of the same element with the same number of protons and same number of electrons but with <span>different number of neutrons. They differ in the number of neutrons that is why they also differ in mass numbers. Since they have the same number of protons, they have the same atomic number.
For instance, when the nucleus of the isotope with a 68.926 amu, there are 30 protons and 39 neutrons in the nucleus. The best example for this is Zn (zinc-69 isotope) and Ga (gallium-69 isotope) which has 68.926 amu and 68.925 amu respectively. </span></span>

3 0

4 years ago