All categories

3 years ago

The purpose of an indicator is to

2 answers:

8 0

Chemical indicators are used to identify when a reaction has undergone a chemical change or if it has reached completion.

Korvikt [17]3 years ago

8 0

Test and determine the pH values of unknown solutions

You might be interested in

1) The spectrum of lithium has a red line of 670.8 nanometers. (Remember 1 m = 1 X 109 nm) a. Convert the nanometer to meter usi

puteri [66]

E = ħc / λ
ħ = plancks constant = 6.626x10^-34 Js
c = speed of light = 2.999x10^8 m/s
λ = wavelength of light = 670.8x10^-9 m

E = (6.626x10^-34 Js) x (2.999x10^8 m/s) x (1 / 670.8x10^-9 m)
E = 2.962x10^-19 J

3x10^8 / (670.8 * 10^-9) =4.47x10^14 Hz

4.47x10^14 Hz multiplied by plank's constant = 2.9634x10^-19

Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions here.

5 0

3 years ago

What two elements do not need eight valence electrons to stay stable?

coldgirl [10]

Hydrogen and helium because they only have one electron shell and it only holds up to two electrons in it.

7 0

3 years ago

How could you demonstrate boiling point?

EleoNora [17]

A light layer of vacuum grease is applied to the rim of the belljar. Water at room temperature is placed inside and the vacuum pump is then used to evacuate the vessel. When the air pressure is reduced to the vapour pressure of water at room temperature the water will begin to boil.

5 0

3 years ago

State whether the following statements are true or false (with justification). (a) 1 mol of N2 has more molecules than 1 mol of

MAVERICK [17]

Answer:

A. False.

Every substance contains the same number of molecules i.e 6.02x10^23 molecules

B. False.

Mass conc. = number mole x molar Mass

Mass conc. of 1mole of N2 = 1 x 28 = 28g

Mass conc. of 1mol of Ar = 1 x 40 = 40g

The mass of 1mole of Ar is greater than the mass of 1mole of N2

C. False.

Molar Mass of N2 = 2x14 = 28g/mol

Molar Mass of Ar = 40g/mol

The molar mass of Ar is greater than that of N2.

Explanation:

7 0

3 years ago

How can one kg of iron melt more ice than 1 kg lead at 100 °C

Vanyuwa [196]

Answer:

Due to the specific heat capacity of iron, 0.444 J/(g·°C), is more than the specific heat capacity for lead, 0.160 J/(g·°C)

Explanation:

The given parameters are;

The metals provided to melt the ice and their temperature includes;

One kg (1000 g) of iron;

Specific heat capacity = 0.444 J/(g·°C)

Temperature = 100°C

1 kg (1000 g) of lead

Specific heat capacity = 0.160 J/(g·°C)

Temperature = 100°C

Therefore, the heat provided to the ice of mass m, and latent heat of 334 J/g at 0°C by the metals are as follows;

For iron, we have;

ΔQ = Mass × Specific heat capacity × Temperature change

ΔQ $_{iron}$ = Heat obtained from the iron by the ice

ΔQ $_{iron}$ = 0.444 m × 1000 × (100 - 0) = 44400 J

Heat absorbed by the ice for melting, H $_l$ = Heat obtained from the iron

∴ Heat absorbed by the ice for melting, H $_l$ = Mass of ice × Latent heat of ice

H $_l$ = Mass of ice × 334 J/g = 44400 J

Mass of ice melted by the iron = 44400 J/334 (J/g) ≈ 132.9 g

Mass of ice melted by the iron ≈ 132.9 g

For lead, we have;

ΔQ = Mass × Specific heat capacity × Temperature change

ΔQ $_{lead}$ = Heat obtained from the iron by the ice

ΔQ $_{lead}$ = 0.160 m × 1000 × (100 - 0) = 16000 J

Heat absorbed by the ice for melting, H $_l$ = Heat obtained from the iron

∴ Heat absorbed by the ice for melting, H $_l$ = Mass of ice × Latent heat of ice

H $_l$ = Mass of ice × 334 J/g = 16000 J

Mass of ice melted by the lead = 16000 J/334 (J/g) ≈ 47.9 g

Mass of ice melted by the lead ≈ 47.9 g

Therefore, mass of ice melted by the iron, approximately 132.9 g, is more than mass of ice melted by the lead, approximately 47.9 g.

3 0

3 years ago