All categories

3 years ago

Explain why we did not see distinct lines (like on an emission spectrum) when the metal salts were burned.

1 answer:

6 0

Actually when we burn metal salts, we cannot actually really see distinct lines to appear because in reality, they are not really visible to the human eye. There is only a certain range of wavelength of light that our eyes can see.

To state in other way, some metal salts will give off light which has wavelengths that are outside of the visible region of the electromagnetic spectrum.<span> </span>

You might be interested in

(a) The absorbance of mixture at 400 nm was 0.40.

laiz [17]

Answer:

0.1 g/dl

Explanation:

The standard curve is a graph that relates the absorbance at 400 nm with the concentration of haemoglobin in mg/dl. To obtain the concentration from the absorbance value, we enter in the x-axis (absorbance at 400 nm) with the value 0.40 (the line between 0.2 and 0.6), we extrapolate the line to the curve and read the correspondent value on y-axis (concentration in mg/dl): 100 mg/dl.

So, we convert the concentration from mg/dl to g/dl by dividing into 1000:

100 mg/dl x 1 g/1000 mg = 0.1 g/dl

Therefore, the concentration of haemoglobin of the patient is 0.1 g/dl.

6 0

3 years ago

Write a method that could be used to produce pure crystals of copper chloride from copper oxide and hydrochloric acid.

joja [24]

- Describe how you would make the salt from the reactants.

CuO + 2 HCl → CuCl₂ + H₂O

- Describe how you would purify the salt from the reaction mixture.

Filter the solution and let the product crystallize.

Explanation:

The reaction between copper oxide (CuO) and hydrochloric acid (HCl) will produce copper chloride (CuCl₂) and water:

CuO + 2 HCl → CuCl₂ + H₂O

-Describe how you would make the salt from the reactants

In a beaker which contain cooper oxide add the hydrochloric acid. To avoid working with concentrated hydrochloric acid, the acid may be diluted with water but make sure the add the stoechiometric amount (and a little bit of excess) in respect with the copper oxide.

-Describe how you would purify the salt from the reaction mixture.

Let the reaction proceed and then filter the solution to remove the unreacted cooper oxide.

Let the filtered solution, which contain copper chloride, water and unreacted hydrochloric acid, to stand undisturbed for several days. You may see the crystals growing from the solution. To speed up the process you may reduce the temperature.

Learn more about:

purifying compounds

brainly.com/question/5586971

brainly.com/question/4757187

#learnwithBrainly

3 0

4 years ago

A mixture of gases contains 4.46 moles of neon (Ne), 0.74 mole of argon (Ar), and 2.15 moles of xenon (Xe). Calculate the partia

viva [34]

Explanation:

The partial pressure of an individual gas is equal to the total pressure of the mixture multiplied by the mole fraction of the gas.

Total pressure = 2atm

Mole Fraction = number of moles / total number of moles

Neon

Mole Fraction = 4.46 / 7.35 = 0.607

Partial Pressure = 0.607 * 2 = 1.214 atm

Argon

Mole Fraction = 0.74 / 7.35 = 0.101

Partial Pressure = 0.101 * 2 = 0.202 atm

Xenon

Mole Fraction = 2.15 / 7.35 = 0.293

Partial Pressure = 0.293 * 2 = 0.586 atm

5 0

3 years ago

Hydrogen bonds are in the family of Van der Waals forces. They are weaker than ionic and covalent bonds but they cause interesti

-Dominant- [34]

Answer:

The answer is B. Van der Waals forces are weaker than ionic and covalent bonds.

Explanation:

In general, if we arrange these molecular forces from the strongest to weakest, it would be like this:

Covalent bonds > Ionic bonds > Hydrogen bonds > Dipole-Dipole Interactions > Van der Waals forces

Covalent bonds are known to have the strongest and most stable bonds since they go deep and into the inter-molecular state. A diamond is an example of a compound with this characteristic bond.

Ionic bonds are the next strongest molecular bond following covalent bonds. This is due to the protons and electrons causing an electro-static force which results to the strong bonds. An example would be Sodium Chloride (NaCl), which when separated is Na⁺ and Cl⁻.

Van der Waals forces, also known as Dispersion forces, are the weakest type of molecular bonds. They are only formed through residual molecular attractions when molecules pass by each other. It doesn't even last long due to the uneven electron dispersion. It can be made stronger by adding more electrons in the molecule. This kind of molecular bonds appear in non-polar molecules such as carbon dioxide.

HOPE THIS HELPS!!!!!!!!!!!!!!

///////////////////////////////////////////////////////////////////////////////////////////

7 0

3 years ago

Sam believes the rock is more denser than the pencil. He measured the mass of the rock to be 8.5 grams and volume to be 4.5mL. H

mezya [45]

Answer:

Rock

Explanation:

Let's calculate the density of each object:

Rock:

$Density = \frac{mass}{volume}=\frac{8.5\ g}{4.5\ mL}=1.9\ g/mL$

Pencil:

$Density = \frac{mass}{volume}=\frac{2.4\ g}{4.5\ mL}=0.53\ g/mL$

Therefore the rock is denser.

6 0

3 years ago