Answer:
2.5 moles of Al
Explanation:
We'll begin by calculating the number of mole in 127 g of Al₂O₃. This can be obtained as follow:
Mass of Al₂O₃ = 127 g
Molar mass of Al₂O₃ = 101.961 g/mol
Mole of Al₂O₃ =?
Mole = mass / molar mass
Mole of Al₂O₃ = 127 / 101.961
Mole of Al₂O₃ = 1.25 mole
Finally, we shall determine the number of mole of Al that reacted. This can be obtained as follow:
4Al + 3O₂ —> 2Al₂O₃
From the balanced equation above,
4 moles of Al reacted to produce 2 moles of Al₂O₃.
Therefore, Xmol of Al will react to produce 1.25 moles of Al₂O₃ i.e
Xmol of Al = (1.25 × 4)/2
Xmol of Al = 2.5 moles.
Thus, 2.5 moles of Al is needed for the reaction.
Mg (s) + 2 HCl (aq) -> MgCl2 (aq) + H2 (g)
1) Number of mols of HCl, n
n = 6.3 L * 4.5 mol/L = 28.35 mol
2) ratio: 2 mol HCl / 1 mol Mg = 28.35 mol HCl / x mol Mg
x = 28.35 mol HCL * 1 mol Mg / 2 mol HCL = 14.175 mol Mg
3) Convert mol to mass using atomic mass of Mg
14.175 mol Mg * 24.3 g Mg / mol Mg = 344. 45 g
Answer: 344.45 g
Explanation:
Metals react with oxygen to form basic oxides while they react with water to form alkaline solutions. Also, acidic oxides are oxides of nonmetals and they react with water to form acidic solutions.
Trends on the period table shows the variation of metallic character as you move across and down the periodic table. Metallic character of a element decreases across the period on the periodic table from left to right because atoms readily accept electrons in their outermost shell to form stable configurations. Metallic character increases as you move down the group in the periodic table and this is because electrons become easier to lose as the atomic radius increases (more outer shells are added), where there is decreasing attraction between the nucleus and the valence electrons.
So down the group, the acidity of oxide reaction with water decreases because the oxides are more basic down the group while across the period, the acidity of oxide increases because acidic oxides are formed as we move across the period.
Answer:
1.6g/mL
Explanation:
Density equation is D=m/v
Density = g/mL
m=mass of sample in grams
v = volume of sample in mL
The volume of a square can be calculated by V=l*w*h.
In this case it is 5cm*5cm*5cm = 125cm^3
Since we know that 1cm^3 ~ 1mL we can convert the volume to mL as so:
125cm^3 (1mL/(1cm^3)) = 125mL
Then simply plug into the density equation:
D=200g/125mL = 1.6g/mL
Silicon has 14 protons Potassium has 19 electrons The neutrons are equal to the mass number minus the atomic number. Or the big number minus the small number on the periodic table. hydrogen 1 does not have a neutron.
iron =56 -26 for 30 neutrons in the nucleus
Chlorine 17 protons and 17 electrons. 18 or 19 neutrons on average.
