16. Representative elements are those found in the *

Ugo [173]

The Moon turns on its axis and orbits earth in the same amount of time

4 0

3 years ago

Which of the following is true about the melting temperature of potassium chloride? The melting temperature is relatively high.

allochka39001 [22]

Answer:f

First option: the melting temperature is relatively high.

Explanation:

You can look at the melting temperature at any table that summarizes the main properties of this compound, potassium chloride.

Such melting point is 770 °C, which is relatively high.

Why is this?

Potassium chloride is a ionic compound formed by the cations of potassium, K⁺, and the chloride anions, Cl⁻. Its unit formula is KCl.

The ionic bond between K and Cl is possible because each K atom is able to yield its valence electron to one Cl atom which has 7 valence electrons.

Then, the K atoms become positive ions (cations) K⁺, while Cl atoms become negative ions (Cl⁻).

These two ions with opposite charge are bonded by the force of electrostatic attraction. This is a ionic bond.

Melting point, so as boiling point along with other physical properties, depends on the attraction force between the atoms.

Hence, since the attrative forces between the ions are relatively strong, the melting point of the ionic compounds, such as potassium chloride, are relatively high.

8 0

3 years ago

Which is the fastest in the universe apart from the light

Salsk061 [2.6K]

Well i did some research and i found out now im not sure if this is completely true but supposedly tachyons are even faster than the speed of light

3 0

3 years ago

Dna is approximately 2.5 nm in length. of an average man is 5 ft 10 in. tall, how many dna molecules could be stacked to extend

Angelina_Jolie [31]

To determine the number of dna molecules that can be stacked as requested in this item, we convert the given measurements in a single unit. For simplicity, we convert all the lengths to meters.

Length of DNA molecule = (2.5 nm)(1 x 10^-9 m/1 nm) = 2.5 x 10^-9 nm

Height of a person = (5 ft 10 in)(12 inches/ 1ft)(2.54 cm/1 in)(1 x 10^-2 m/ 1 cm)
= 1.778 m

Then, divide the height of the person by the length of a single DNA molecule.

n = 1.778 m / (2.5 x 10^-9)
n = 7.112 x 10^8

Hence, the number of DNA would be 7.112 x 10^9.

5 0

4 years ago

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How many grams of CaCl2 should be dissolved in 445.2 mL of water to make a 0.19 M solution of CaCl2?

maksim [4K]

In order to solve this, you will need to know how many moles of CaCl2 you will need, and to do so, you must look at the concentration of the solution.

You are told that the concentration of the solution is 0.19M, meaning that there is 0.19 moles of CaCl2 for every 1 liter of solution. However, you don't have 1 liter of solution, you have 445.2 mL. You must convert this to liters by dividing by 1000.

445.2 mL * (1 L / 1000 mL) = 0.4452 L

Now, you can solve for how many moles the solution must have. Since M = mol / L and you are given M and L, you can set up an equality as follows:

0.19M = mol / 0.4452 L

Now, in order to find the number of moles, you multiply both sides by 0.4452L

0.19M * 0.4452 L = moles = 0.084588mol

Now, you must calculate the molar mass of CaCl2 by using the periodic table

MM Ca = 40.078 g/mol

MM Cl = 35.452 g/mol

40.078 + (35.452 * 2) = 110.982 g/mol

Now you multiply the number of moles in the solution you calculated by the molar mass.

0.084588mol * 110.982 g/mol = 9.387 g CaCl2

6 0

3 years ago

Read 2 more answers