Two aircraft rivets, one of iron and the other of copper, are placed in a calorimeter that has an initial temperature of 10â°c. the data for the metals are as follows: iron copper mass(g) 39.0 13.0 initial t (â°c) 0.0 100.0 c(j/gâ·k) 0.450 0.387 (a) will heat flow from fe to cu or from cu to fe? cu to fe fe to cu (b) to determine the actual final temperature, what must be known? the volume of the calorimeter the heat capacity of the calorimeter the density of the metals

a) Copper is at a higher temperature, so the flow of heat will take place from copper to iron. Heat is a form of energy, which always flows from higher temperature to lower temperature.  

b) To determine the actual final temperature, the heat capacity of the calorimeter must be known. A calorimeter constant refers to a constant, which quantifies the heat capacity of a calorimeter. It may be determined by using a known amount of heat to the calorimeter and measuring the corresponding change in temperature of the calorimeter.  

(a) Cu to Fe

(b) heat capacity of the calorimeter

Explanation:

(a) Will heat flow from Fe to Cu or from Cu to Fe?

We need to consider the initial temperatures:

Cu 100.0°C

Fe 0.0 °C

Calorimeter 10 °C

Heat flows from bodies with higher temperatures to bodies with lower temperatures. So, heat will flow from Cu to Fe and to the calorimeter.

(b) To determine the actual final temperature, what must be known?

To determine the final temperature of the system, we need to know the amount of heat absorbed by the calorimeter (Qcal). We can calculate it using the following expression.

Qcal = C . ΔT

where,

C: heat capacity of the calorimeter

ΔT: change in the temperature

Thus, we need to know the heat capacity of the calorimeter.

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2

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.