Aluminum reacts with excess aqueous hydrochloric acid to produce hydrogen. (a) write a balanced chemical equation for the reaction. (hint: water-soluble alcl3 is the stable chloride of aluminum.) (b) calculate the mass of pure aluminum that will furnish 10.0 l hydrogen at a pressure of 0.750 atm and a temperature of 30.0°c.

5.39 g

Explanation:

The balanced equation for the reaction of aluminum with hydrochloric acid is shown below as:-

Given,

Pressure = 0.750 atm

Temperature = 30.0 °C

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15  

So,  

T = (30.0 + 273.15) K = 303.15 K  

T = 303.15 K  

Volume = 10.0 L

Using ideal gas equation as:

PV=nRT

where,  

P is the pressure

V is the volume

n is the number of moles

T is the temperature  

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

0.750 atm × 10.0 L = n × 0.0821 L.atm/K.mol × 303.15 K  

⇒n = 0.3013 moles

Moles of hydrogen obtained = 0.3013 moles

From the reaction,

3 moles of hydrogen gas are furnished when 2 moles of aluminum is consumed.

Also,

1 mole of hydrogen gas are furnished when mole of aluminum is consumed.

Thus,

0.3013 mole of hydrogen gas are furnished when mole of aluminum is consumed.

Moles of aluminum consumed = 0.2 moles

Also, Molar mass of aluminum = 26.981539 g/mol

So, Mass = Moles*Molar mass = 0.2 moles*26.981539 g/mol  =  5.39 g

c is the answer because when something is left after something evaporates that shows the chemical change.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.