Answer is: there are 3.011·10²³ atoms of calcium.
n(Ca) = 0.50 mol; amount of substance(calcium).
Na = 6.022·10²³ 1/mol; Avogadro's constant or number.
N(Ca) = n(Ca) · Na.
N(Ca) = 0.50 mol · 6.022·10²³ 1/mol.
N(Ca) = 3.011·10²³; number of calcium atoms.
The mole is an SI unit which measures the number of particles in substance. One mole is equal to <span><span>6.022</span></span>·<span><span><span>10</span></span></span>²³<span> atoms.</span>
I have attached a photo of the structure.
You can get better at solving problems like this by practicing a lot!
I'm guessing you mean O2 gas? This is an elemental compound. It can't be a mixture because it is composed of only 1 element. Hope I helped!
When the atmospheric pressure is equal to the vapor pressure of the liquid, boiling of liquid will begin.
<h3>What happens when atmospheric pressure is equal to the vapor pressure of liquid?</h3>
When the atmospheric pressure is equal to the vapor pressure of the liquid, boiling will begin. The bubbles formation started to the liquid molecules which have gained enough energy to change to the gaseous phase.
The vapor pressure of ethanol is 5.95 kPa at 20.0 °C, and its vapor pressure is 53.3 kPa at 63.5 °C.
Learn more about pressure here: brainly.com/question/25965960
