Answer:
Explanation:
Volume of metal = volume of water displaced = (30.0 - 25.0) ml = 5.0 ml
Density of metal = 5.50 g/ml
Mass of metal =
Volume of water = 25.0 ml
Density of metal = 1.0 g/ml
Mass of metal =
As we know that,
.................(1)
where,
q = heat absorbed or released
= mass of metal = 27.5 g
= mass of water = 25.0 g
= final temperature = ?
= temperature of metal =
= temperature of water =
= specific heat of lead = ?
= specific heat of water=
Now put all the given values in equation (1), we get
Thus the specific heat of the unknown metal sample is
Answer:
0.018 moles of isooctane must be burned to produce 100 kJ.
Explanation:
When the isooctane is <em>burned</em>, it undergoes a reaction known as combustion, in which reacts with oxygen to produce carbon dioxide and water. In standard conditions (Pressure = 1 atm and Temperature = 298 K) formed water is liquid. The balanced equation is:
C₈H₁₈(l) + 12.5 O₂(g) ⇄ 8 CO₂(g) + 9 H₂O(l)
The standard enthalpy of combustion (which can be found in tables) relates the amount of isooctane that reacts and the heat the reaction liberates. In this case, ΔH°c = -5,460 kJ/mol, that is every 1 mol of isooctane that burns, 5,460 kJ of heat are released.
We can begin with the information of 100 kJ and apply this conversion factor. Since this energy is released, by convention, we write it with a minus sign.
A). Carbon enters the atmosphere as carbon dioxide from respiration and combustion.
Think of it this way: it is a distribution problem in which you are multiplying the 2 on the outside with each element in the parentheses. Oxygen does not have a number in front of it, so put an imaginary one in front of it to help you. Do the same with Hydrogen since it doesn't have a number in front of it either. Now you know that hydrogen has one ion and oxygen has one... but you must now multiply each of the elements' ions by two. You should now know that Oxygen has 2 ions in Calcium Hydroxide and that there are also 2 ions of Hydrogen in Calcium Hydroxide. Does this make sense?