Answer:
The wavelength of radio wave is 3m
Explanation:
speed of r.w (v) = 3 × 10⁸ m/s
frequency (f) = 1 × 10⁸ Hz
wavelength (λ) = ?

λ = v/f
= (3 × 10⁸) ÷ (1 × 10⁸)
= 3m
(Correct me if i am wrong)
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.
Answer:
3.2043 x 10²³
Explanation:
No. of Mole of lead (Pb) = 0.532 mol
No. of atoms of lead = ?
Solution:
Formula Used to calculate
no. of moles = numbers of particles (ions, molecules, atoms) /Avogadro's number
Avogadro's no. = 6.023 x10²³
So,
The formula could be written as
no. of atoms of lead Pb = no. of moles x 6.023 x10²³
Put the values in above formula
no. of atoms of lead Pb = 0.532 mol x 6.023 x10²³
no. of atoms of lead Pb = 3.2043 x 10²³
so 3.2043 x 10²³ atoms of lead are contained in 0.532 mole.
Well depends how fast they're going if it's a slow speed a bus but at a fast speed a bike because you wanna be careful while stopping
By atomic radius, the bottom left