The atomic number is based on the number of protons, so the atomic number would be 43
Ok so, remember that t<span>he average atomic mass is what is seen on the periodic table. It is the average mass of all of the isotopes with their frequency taken into account. What you need to do is add the products of the masses and frequencies Just like this:</span>
<span>0.903*267.8 + 0.097*270.9
When you add it the result is what you are looking for</span>
4 mol / 205g H2O = 4/.205 = 19.5 mol/kg boiling point = 100 + 19.5 • 0.51 = 109 ºC
Answer:
+1
Explanation:
A Potassium atom is represented with the sign "K" in chemistry and have atomic number 19.
The charge of electrons causes a matter to experience a force and it can be positive or negative.
In Potassium atom, the electric charge is +1 to enter a stable electron configuration as there is only one valence electron in the outermost shell of potassium atom. As potassium atom will lose electron it will become positively charged.
Hence, the correct answer is "+1".
Here's how to do it:
<span>Balanced equation first: </span>
<span>Mg + HCl = H2 + MgCl2 unbalanced </span>
<span>Mg + 2 HCl = H2 = MgCl balanced </span>
<span>Therefore 1 mole Mg reacts with 2 moles Hcl. </span>
<span>50g Mg = ? moles (a bit over 2; you work it out) </span>
<span>75 g HCl = ? moles (also a bit over 2; you work it out) </span>
<span>BUT, you need twice the moles HCl; therefore it is the Mg that is in excess. (you can now work out how many moles are in excess, and therefore how much mg is left over). </span>
<span>So, 2 moles HCl produce 1 mole H2(g) </span>
<span>therefore, the amount of H2 produced is half the number of moles of HCl </span>
<span>At STP, there are X litres per mole of gas (look it up - about 22 from memory) </span>
<span>Therefore, knowing the moles of H2, you can calculate the volume</span>
