Hello Gary!
*Sorry if I'm late*
Your answer is going to be 65.
Element A (which is actually Zinc) has the atomic number of 65. (I remember having got memorize this also).
Pretty much the explanation is that the number of patrons is equivalent to the element's atomic number!
Hope this helps!
Have a nice day :D
Answer:
mass= no.of atoms present× atomic mass
no. of moles=given mass÷molar mass
#follow these u'll get ur ans in numericals
Answer:
Ni^2+(aq) + CO3^2-(aq) -----> NiCO3(s)
Explanation:
First let us put down the molecular equation of the reaction
Na2CO3(aq) + Ni(NO3)2(aq)----> 2NaNO3(aq) +NiCO3(s)
Hence ionically, we will have the reaction as;
Ni^2+(aq) + CO3^2-(aq) -----> NiCO3(s)
The ionic equation usually indicate the ions that actually take part in the reaction. They often lead to the formation of the solid product or precipitate.
The order ions that are no shown in the ionic reaction equation are called spectator ions.
Hence, the reaction shown in the answer is the ionic reaction equation for the mixing of nickel II nitrate and sodium carbonate.
Answer:
38.36 L.
Explanation:
- We can use the general law of ideal gas: PV = nRT.
where, P is the pressure of H₂ in atm (P = 1.0 atm, STP conditions).
V is the volume of H₂ in L (V = ??? L).
n is the no. of moles of H₂ in mol (n = mass/molar mass = (10.0 g)/(2.0 g/mol) = 5.0 mol).
R is the general gas constant (R = 0.0821 L.atm/mol.K),
T is the temperature of H₂ in K (T = 0.0°C + 273 = 273.0 K, STP conditions).
<em>∴ V = nRT/P</em> = (5.0 mol)(0.0821 L.atm/mol.K)(273.0 K)/(1.0 atm) = <em>38.36 L.</em>
Question 16:
We are given the following balanced equation: (Remember to always balance the equation)
We are also told that Mg(OH)2 is in excess, meaning HNO3 is the limiting reactant, we will use its moles to find the number of moles of Mg(NO3)2, then we can convert that to mass.
The ratio between HNO3 and Mg(NO3)2 is 2:1
Therefore the number of moles of Mg(NO3)2 = 8.00 mol x (1/2) = 4.00 mol
Now we can convert the number of moles of Mg(NO3)2 to mass: molar mass of Mg(NO3)2 = 148,3 g/mol
So the mol will cancel the mol, then you will be left with g.