Question

A materials scientist has created an alloy containing aluminum, copper, and zinc, and wants to determine...

A materials scientist has created an alloy containing aluminum, copper, and zinc, and wants to determine the percent composition of the alloy. The scientist takes a 12.921 g sample of the alloy and reacts it with concentrated HCl. The reaction converts all of the aluminum and zinc in the alloy to aluminum chloride and zinc chloride in addition to producing hydrogen gas. The copper does not react with the HCl. Upon completion of the reaction, a total of 10.5 L of hydrogen gas was collected at a pressure of 738 torr and a temperature of 27.0 °C. Additionally, 2.673 g of unreacted copper is recovered. Calculate the mass of hydrogen gas formed from the reaction.

also, Calculate the mass of aluminum in the alloy sample.

aswell as, What is the mass percent composition of the alloy? (for Cu, Al, and Zn)

please be detailed!

Homework Answers

Answer #1

Mass of hydrogen gas

Using the ideal gas equation

PV = nRT

738/760 * 10.5 = n * 0.0821 * 300

n = 0.41396 moles

Molar mass of H2 gas = 2 gm/mol

Mass of hydrogen gas formed = 0.41396 moles * 2 gm/mol = 0.82793 moles

Mass of aluminium and zinc in sample = 12.921 - 2.673 = 10.248 gms

Let the mass of aluminium be x and mass of zn be (10.248-x)

x/27 * 3/2 + (10.248-x)/65.38 * 1 = 0.41396

x/18 + 0.1567 - 0.01529x = 0.41396

0.04026x = 0.25726

x = 6.3899 gms

Mass of zinc = 10.248 - 6.3899 = 3.8580

Mass percent of al = 6.3899/12.921 * 100 = 49.45%

mass percent of zinc = 3.8580/12.921 * 100 = 29.85%

mass percent of cu = 2.673/12.921 * 100 = 20.689%

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
a particular sample of a zinc-aluminum alloy weighs 3.00 g and has mass percentages of 72.5%...
a particular sample of a zinc-aluminum alloy weighs 3.00 g and has mass percentages of 72.5% Zn and 27.5% Aluminum. a) How many moles of each element is in the alloy sample? b) How many theoretical moles of H2(g) will be produced by the reaction of HCl (aq) with each metal and what will be the total number of moles produced? c) How many actual moles of H2(g) will be produced by the reaction of HCl (aq) with each metal...
a particular sample of zinc-aluminum alloy weighs 3.00 g and has mass percentages of 73.5% Zn...
a particular sample of zinc-aluminum alloy weighs 3.00 g and has mass percentages of 73.5% Zn and 26.5% Al. a. how many moles of each element is in the alloy sample? b. how many theoretical moles of H2 (g) will be produced by the reaction of HCl aq with each metal and what will be the total number of moles produced?
The zinc within a copper-plated penny will dissolve in hydrochloric acid if the copper coating is...
The zinc within a copper-plated penny will dissolve in hydrochloric acid if the copper coating is filed down in several spots (so that the hydrochloric acid can get to the zinc). The reaction between the acid and the zinc is as follows: 2H+(aq)+Zn(s)→H2(g)+Zn2+(aq). When the zinc in a certain penny dissolves, the total volume of gas collected over water at 25 ∘C was 0.959 L at a total pressure of 752 mmHg. What mass of hydrogen gas was collected?
a)How is it possible to determine if CaCO3 is Cl- free after synthesis? b)How can the...
a)How is it possible to determine if CaCO3 is Cl- free after synthesis? b)How can the Cl- ions be remove from CaCO3 after synthesis? I should answer the questions from the following experiment but if you know the answer and you are sure, yo do not need to read experiment. Please answer correctly because i hav no chance to make wrong :(((( Physical and Chemical Properties of Pure Substances Objective The aim of today’s experiment is to learn handling chemicals...
Procedure Reaction 1: Dissolving the Copper 1. Obtain a clean, dry, glass centrifuge tube. 2. Place...
Procedure Reaction 1: Dissolving the Copper 1. Obtain a clean, dry, glass centrifuge tube. 2. Place a piece of copper wire in a weighing paper, determine the mass of the wire and place it in the centrifuge tube. The copper wire should weigh less than 0.0200 grams. 3. In a fume hood, add seven drops of concentrated nitric acid to the reaction tube so that the copper metal dissolves completely. Describe your observations in the lab report. (Caution, Concentrated nitric...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT