Magnesium-aluminum alloys are commonly used in aircraft construction. When
treated with acid, both metals react to form hydrogen gas, as shown in the unbalanced
chemical equations below. A 1.000 g sample of alloy produces 0.107 g of H2 (g) when reacted
with excess HCl (aq). What is the percent composition by mass of Al in the alloy?
Al (s) + HCl (aq) à AlCl3 (aq) + H2 (g)
Mg (s) + HCl (aq) à MgCl2 (aq) + H2 (g)
2Al + 6HCl ------> 2AlCl3 + 3H2 .....(1)
Mg + 2HCl -----> MgCl2 + H2 ......(2)
Let mass of Al in alloy = (x) g
Moles of Al = mass/molar mass = x/27 moles
Then, mass of Mg in alloy = (1 - x) g
Moles of Mg = mass/molar mass = (1 - x)/24 moles
From reaction;
2 mole Al produces 3 moles H2
So, x/27 mole Al will produce = 1.5 * (x/27) moles of H2 = 1.5x/27 moles
Moles of H2 = 1.5x/27
From reaction (2)
1 moles Mg produces 1 mole H2
So, (1-x)/24 mole Mg will produce = (1-x)/24 moles of H2
Moles of H2 = (1 - x)/24
Total moles of H2 = (1.5x/27) + ((1 - x)/24)
= (1.5x*24 + 27 - 27x)/(27*24) = (9x + 27)/648 moles = (x+3)/72
Total mass of H2 = moles * molar mass = ((x+3)/72)*2 = (x+3)/36 g
So,
x+3/36 = 0.107
x = 0.852 grams
So,
% of Al in x = 0.852*100/1 = 85.2 % ..... Answer
Magnesium-aluminum alloys are commonly used in aircraft construction. When treated with acid, both metals react to form...
Some two equation/Two unkown Problem Magnesium and aluminum react with acid to give hydrogen gas. What volume of hydrogen gas measured at 25°C and a pressure of 0.985 atm can be obtained from 4.00 g of an alloy that is 20.0 Mg and 70.0 Al? Mg (s) 2 H (aq) H2 (g) Mg (aq) +2 2 Al (s) 6 H (aq) 3 H2 (g) 2 Al 3 (aq) 1. A 2.05 g sample of an iron-aluminum alloy (ferroaluminum) is dissolved...
When active metals such as magnesium are immersed in acid solution, hydrogen gas is evolved. Calculate the volumeſin L) of H2(g) at 35.2°C and 646 torr that can be formed when 325 ml of 0.855 M HCl solution reacts with excess Mg to give hydrogen gas and aqueous magnesium chloride Mg(s) + HCl(aq) --MgCl2(aq) + H2(g) (unbalanced) Write answer to three significant figures. Numeric Response
Calculate the theoretical yield in moles of magnesium chloride when 46 grams of Mg(s) react with 48 grams of HCl(aq). Write the answer using 2 decimal places and do not use scientific notation. Mg(s) + HCl (aq) --> MgCl2(aq) + H2(g) UNBALANCED
If 0.42 moles of aluminum react with excess hydrochloric acid, what is the volume of hydrogen produced at 0.95 atm and 27 °C? 2 Al(s) + 6 HCl(aq) + 2 AlCl3 (aq) + 3 H2(g) O 11L O 5.4L 16 L C33L
8 pts 25. Aluminum metal (0.100 mol) and a volume of aqueous hydrochloric acid that contains 0.500 mol of HCl are combined and react to completion. How many liters of hydrogen gas, measured at STP are produced? Al(s) + HCl(aq) - AICI3(aq) + H2(g) (unbalanced) 4.48 L of H2 5.60 L of H2 224 L of H2 3.36 L of H2 6.72 L of H2
When solid magnesium is reacted with an aluminum phosphate solution, metallic aluminum is produced by single displacement (equation. a): (a) AlPO4(aq)+Mg(s)→Al(s)+Mg3(PO4)2(aq) Balance equation (a) and answer the following: How many grams of aluminum metal should be theoretically produced from 2.338 g of pure magnesium metal. Suposse magnesium metal is the limiting reactant. Molar masses (g/mol): AlPO4 = 121.95 Mg = 24.305 Al = 26.98 Mg3(PO4)2 = 262.86 Important note: Use 3 digits after the decimal place in your answer.
2) Hydrogen gas is produced when aluminum reacts with hydrochloric acid: Al(s) + HCl(aq) AlCl3(aq) + H2(g) [Unbalanced] - If 940.1 mL of wet hydrogen is collected over water at 23.7 °C and a barometric pressure of 748.69 torr, how many grams of Al have been consumed? (The vapor pressure of water at 23.7 °C is 21.98 mmHg) 3) Follow auf bau principle for the questions below. Formatting must be done correctly. a) Type the complete electron configuration of Rb...
7) Magnesium hydroxide, Mg(OH)2, as "Milk of Magnesia" can be used to neutralize excess stomach acid, represented by HCl(ag) according to the chemical equation below. Mg(OH)2(s)+2HCI (ag)-MgCl2(ag)+ 2H20( When 5.00 g of HCl are combined with an excess of Mg(OH)2, what mass of MgCl2 can be produced? [Molar masses: H, 1.01 g/mol; O, 16.00 g/mol; Mg, 24.31 g/mol; Cl, 35.45 g/mol] A) 2.50 g E) 70.5 g D) 6.53 g C) 0.957 g B) 13.1 g 8) What is the...
Food and beverage containers are commonly made of tin, steel, aluminum, or a combination of metals. Suppose that a laboratory procedure requires a can be made of aluminum. Which property can be used to determine if a can is likely to be made of aluminum? O color Odensity volume mass What is the density of a pear that occupies 32 cm and has a mass of 42 g O 0.7619 g-cm 0 2.0 g.cm O 1.3125 g-cm O 0.76 g.cm...
5) How many moles of hydrogen gas are needed to react with oxygen to form one mole of 5) water? 2H2(8) + O268) - 2H20(1) A) 4 mol B) 1 mol C) 2 mol D) 0.5 mol E) 6 mol 6) Incomplete combustion occurs when there is insufficient oxygen to react with a compound. The suffocating gas carbon monoxide is a product of incomplete combustion. How many moles of oxygen gas are required for the complete combustion of 11.0 moles...