<u>Answer:</u> The formula of the compound formed between rubidium and fluorine is RbF
<u>Explanation:</u>
Ionic bond is defined as the bond which is formed by complete transfer of electrons from one atom to another atom.
The atom which looses the electron is known as electropositive atom and the atom which gains the electron is known as electronegative atom. This bond is usually formed between a metal and a non-metal.
Rubidium is the 37th element of the periodic table having electronic configuration of
This will loose 1 electron to form ion
Fluoride is the 9th element of the periodic table having electronic configuration of
This will gain 1 electron to form ion
To form compound, 1 rubidium ion is needed to neutralize the charge on fluoride ion
The formation of the given compounds is shown in the image below.
275 mm = 27.5 cm
45mg = 4.5g
25cm = 250 mm
Not sure about number 8
Answer:
1) 0.00498 mol Cu.
2) 0.00000374 mol CO₂
Explanation:
Question 1)
We want to convert 3.00 * 10²¹ copper atoms into moles. Note that 3.00 is three significant figures.
Recall that by definition, one mole of a substance has exactly 6.022 * 10²³ amount of that substance. In other words, we have the ratio:
We are given 3.00 * 10²¹ Cu. To cancel out the Cu, we can multiply it by our above ratio with Cu in the denominator. Hence:
Cancel like terms:
Simplify:
Use a calculator:
Since the resulting answer must have three significant figures:
So, 3.00 * 10²¹ copper atoms is equivalent to approximately 0.00498 moles of copper.
Question 2)
We want to convert 2.25 * 10¹⁸ molecules of carbon dioxide into moles. Note that 2.25 is three significant digits.
By definition, there will be 6.022 * 10²³ carbon dioxide molecules in one mole of carbon dioxide. Hence:
To cancel the carbon dioxide from 2.25 * 10¹⁸, we can multiply it by the above ratio with the carbon dioxide in the denominator. Hence:
Cancel like terms:
Simplify:
Use a calculator:
Since the resulting answer must have three significant figures:
So, 2.25 * 10¹⁸ molecules of carbon dioxide is equivalent to approximately 0.00000374 moles of carbon dioxide.
Vitamin B is composed of C. 8 compounds. Here they are:
- vitamin B1 is called thiamine
- vitamin B2 is called riboflavin
- vitamin B3 are niacin, nicotinic acid, nicotinamide riboside
- vitamin B5 is pantothenic acid
- vitamin B6 are pyridoxine, pyridoxal, pyridoxamine
- vitamin B7 is biotin
- vitamin B9 is folic acid
- vitamin B12 are cobalamins