Answer:
Tin: 54.3%
Zinc: 45.7%
Explanation:
The molar masses of the elements are:
Tin: Sn = 117.710 g/mol
Zinc: Zn = 65.409 g/mol
Fluorine: F = 18.998 g/mol
The fluorine gas in excess, so the reaction consumes all the alloy, and all the tin is converted to SnF₄ and all the zinc is converted to ZnF₂. The molar masses of the fluorides are:
SnF₄ = 117.710 + 4*18.998 = 193.702 g/mol
ZnF₂ = 65.409 + 2*18.998 = 103.405 g/mol
If we call x the number of moles of SnF₄, and y the number of moles of ZnF₂, the total mass can be calculated knowing that the mass is the number of moles multiplied by the molar mass:
193.702x + 103.405y = 2.489
The number of moles of Sn is the same as SnF₄ (1:1), and also the number of moles of Zn is the same as ZnF₂ (1:1), so the mass of the alloy:
117.710x + 65.409y = 1.540
if we multiply it by -1.581 and sum with the other equation:
117.710x*(-1.581) + 65.409y*(-1.581) + 193.702x + 103.405y = 1.540*(-1.581) + 2.489
7.60249x = 0.05426
x = 0.0071 mol of Sn
117.710*0.0071 + 65.409y = 1.540
65.409y = 0.704259
y = 0.0108 mol of Zn
The masses are the molar mass multiplied by the number of moles:
Sn: 117.710*0.0071 = 0.836 g
Zn: 65.409*0.0108 = 0.704 g
The percent composition is the mass of the substance divided by the total mass multiplied by 100%:
Sn: (0.836/1.540)*100% = 54.3%
Zn: (0.704/1.540)*100% = 45.7%
b. 5.61 L
c. 11.21 L
d. 22.41 L
e. 44.81 L
Mass of Neon : = 24.21564 g
Given
1.2 moles of Neon
Required
mass of Neon
Solution
The mole is the number of particles contained in a substance
1 mol = 6.02.10²³
Moles can also be determined from the amount of substance mass and its molar mass
Mol = mass : Molar mass
so mass of Neon(MM=20,1797 g/mol) :
= mol x MM
= 1.2 x 20,1797
= 24.21564 g
Answer:
Explanation:
That is a chemical property of alkali metals: they are highly reactive and react vigorously with water to produce the correspondant hydroxide and hydrogen gas.
These are some of those reactions:
The alkali metals are the elements of group 1 of the periodic table: Li, Na, K, Rb, Cs, and Fr. They have one valence electron which may lose easily to form an ion with charge +1.
Alkali metals react with water to produce hydrogen gas and a basic solution of the metal hydroxide (for instance, sodium hydroxide when lithium is in the reaction). This reaction signifies the easier oxidation of alkali metals compared to hydrogen.
When alkali metals react with water, they form hydrogen gas and a basic solution of the metal hydroxide. This vigorous reaction reveals that alkali metals are easier to oxidize than is hydrogen. For instance, considering the reaction of lithium with water:
2Li(s) + 2H₂O(l) --> 2NaOH(aq) + H₂(g)
The solid state (s) lithium reacts with liquid water to generate hydrogen gas and the ionic compound sodium hydroxide. This sodium hydroxide, which is a solid in its pure form, promptly dissolves in water.
The same kind of reaction occurs with other alkali metals and also some alkaline earth metals, although beryllium and magnesium are exceptions.
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Answer:
Answer in picture
Explanation:
To calculate the molar mass of a compound, sum the atomic masses of all atoms in the compound. Ammonia has a molar mass of 17.04 g/mol, magnesium hydroxide has a molar mass of 58.33 g/mol, and iron(III) oxide has a molar mass of 159.70 g/mol.
Calculating Molar Mass
To calculate the molar mass of a compound, you sum the atomic masses of each individual element present in the compound, multiplied by the number of each of those atoms in the formula.
Ammonia (NH3): The atomic mass of nitrogen (N) is approximately 14.01 g/mol and hydrogen (H) is approximately 1.01 g/mol. Since ammonia contains one nitrogen atom and three hydrogen atoms, its molar mass would be (14.01 g/mol) + 3 × (1.01 g/mol) = 17.04 g/mol.
Magnesium hydroxide (Mg(OH)2): The atomic mass of magnesium (Mg) is approximately 24.31 g/mol, oxygen (O) is approximately 16.00 g/mol, and hydrogen (H) is again 1.01 g/mol. Magnesium hydroxide has one magnesium atom, two oxygen atoms, and two hydrogen atoms. Thus, its molar mass is (24.31 g/mol) + 2 × (16.00 g/mol) + 2 × (1.01 g/mol) = 58.33 g/mol.
Iron(III) oxide (Fe2O3): The atomic mass of iron (Fe) is approximately 55.85 g/mol and oxygen (O) is 16.00 g/mol. Iron(III) oxide consists of two iron atoms and three oxygen atoms, giving a molar mass of 2 × (55.85 g/mol) + 3 × (16.00 g/mol) = 159.70 g/mol.
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How much CaCl2, in grams, is needed to make 2.0 L of a 3.5M solution?