Explain by means of why is reddish orange is observed when you add sodium chloride

If the half life of a radioactive isotope is 5000 years, how much of the radioactive isotope in a specimen will be left after 10

marissa [1.9K]

Half life is the time taken by a radioactive isotope to decay by half its original mass. In this case, the halflife of the radioactive isotope is 5000 years.
Initially the mass is 100 %; thus the mass that will be left will be given by;
New mass = Original mass × (1/2)^n where n is the number of half lives;
n = 10000/5000 = 2
New mass = 100% ×(1/2)^2
= 100 % × 1/4
= 25%
Therefore; the mass left after 10000 years is 25% or 1/4 of the original mass.

5 0

3 years ago

Compare and contrast solids liquids and gases in terms of volume shape compessibility and energy

tangare [24]

Answer:

solid has definite shape and volume.

liquid do not have definite shape but have definite volume.

gas do not have definite shape and definite volume.

solid have lowest compressibility out of three, liquid have more compressibility than solid but less than gases. gases have the highest compressibility out of three. Molecules in the solid phase have the least amount of energy, while gas particles have the greatest amount of energy. The temperature of a substance is a measure of the average kinetic energy of the particles.

8 0

2 years ago

What is the freezing point of a solution of 498mL of water (solute) dissolved in 2.50 L of ethanol (solvent), C2H5OH? The densit

jok3333 [9.3K]

Answer:

Freezing T° of solution is -142.4°C

Explanation:

This excersise is about colligative properties, in this case freezing point depression,

ΔT = Kf . m . i

Where ΔT = Freezing T° of solvent - Freezing T° of solution

Kf = Cryoscopic constant

m = mol/kg (molality)

i = Number of ions dissolved.

Water is not ionic, so i = 1

Let's find out m.

We determine mass of water, by density

498ml . 1 g/mL = 498 g

We convert the mass of water to moles → 498 g . 1mol/18g = 27.6 moles

We determine mass of solvent by density

2500 mL . 0.789 g/mL = 1972.5 g

Notice, we had to convert L to mL to cancel units.

1 cm³ = 1 mL

We convert the mass from g to kg → 1972.5 g . 1kg /1000g = 1.97kg

We determine m = mol/kg → 27.6mol / 1.97kg = 13.9 m

Kf for ethanol is: 1.99 °C/m

Freezing T° for ethanol is: -114.6°C

We replace at formula: - 114.6°C - Freezing T° solution = 1.99 °C/m . 13.9 m . 1

- 114.6°C - Freezing T° solution = 27.8 °C

- Freezing T° solution = 27.8°C + 114.6°C

Freezing T° Solution = - 142.4 °C

7 0

2 years ago

Determine the volume of an object that has a mass of 455.6 g and a density of 19.3 g/cm3. (1cm3 = 1ml) select one:

Dmitry [639]

The answer is B. The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume.

4 0

3 years ago

If you were to compare a cell to the human body, what organ in the body would have a similar responsibility to the cells nucleus

Amanda [17]

The brain. The brain tells the body what to do same way the nucleus does for the cell.

5 0

2 years ago