Answer:
21.8 grams.
Explanation:
Molar mass data from a modern periodic table:
How many moles of MgO will be produced if Mg is the limiting reactant?
Number of moles of Mg:
.
The ratio between the coefficient of Mg and that of MgO is 2:2. Two moles of Mg will make two moles of MgO. 0.670644 moles of MgO will be produced if Mg is the limiting reactant.
How many moles of MgO will be produced if O₂ is the limiting reactant?
Number of moles of O₂:
.
The ratio between the coefficient of O₂ and that of MgO is 1:2. One mole of O₂ will make two moles of MgO. 
of MgO will be produced if O₂ is in excess.
How many moles of MgO will be produced?
0.541284 is smaller than 0.670644. Only 0.541284 moles of MgO will be produced since O₂ will run out before all 16.3 grams of Mg is consumed.
What's the mass of 0.541284 moles of MgO?
Formula mass of MgO:
.
Mass of 0.541284 moles of MgO:
.
The answer is b. 4.2 mole. The balanced reaction formula is 2LiOH + H2SO4 -->Li2SO4 + 2H2O. And the ratio of mole number of the reactants is the same as the ratio of coefficients.
Answer:
CH3COOH would be more concentrated
Explanation:
The higher the concentration value, the more concentrated it is.
The relationship between concentration, moles and volume is given by the equation;
Concentration = No of moles / Volume
5.0 grams of HCOOH dissolved in 189 mL of water
Number of moles = Mass / Molar mass = 5 / 46.03 = 0.1086 mol
Concentration = 0.1086 / 0.189 = 0.5746 mol/L
1.5 moles of CH3COOH dissolved in twice as much water
Volume = 2 * 189 = 378 ml = 0.378 L
Concentration = 1.5 / 0.378 = 3.9683 mol/L
Comparing both concentration values;
CH3COOH would be more concentrated
Answer: Option (D) is the correct answer.
Explanation:
Valence shell is the shell present on the outermost core of an atom and electrons present in the valence shell are known as valence electrons.
If an atom has completely filled valence shell then it means the atom is not reactive in nature because it is already stable.
But when an atom has less than eight electrons in its valence shell then it means to attain stability the atom will readily attract electrons towards itself.
As the given element 1 has 8 electrons in its valence shell. Hence, it is not reactive in nature but element 2 has 6 valence electrons. So, in order to attain stability element 2 will readily attract 2 electrons from a donor atom.
Thus, we can conclude that element 2 is more reactive because it does not have a full valence shell, so it will attract electrons.
Answer:
c. 1.5 mol
Explanation:
- Firstly, we need to calculate the no, of moles of 39.0 grams of calcium fluoride.
n = mass / molar mass = (39.0 g) / (78.07 g/mol) = 0.499 mol ≅ 0.5 mol.
- CaF₂ ionized in water as:
<em>CaF₂ → Ca⁺² + 2F⁻.</em>
Every 0.1 mole of CaF₂ is ionized to 3 ions (1 ion of Ca⁺² and 2 ions of F⁻).
<em>So, 0.5 mol of CaF₂ will contain (3 x 0.5 mol = 1.5 mol) of ions.</em>
Thus, the right choice is "c. 1.5 mol".
