Answer:
Explanation:
We are asked to find how many kilojoules of energy would be required to heat a block of aluminum.
We will use the following formula to calculate heat energy.
The mass (m) of the aluminum block is 225 grams and the specific heat (c) is 0.897 Joules per gram degree Celsius. The change in temperature (ΔT) is the difference between the final temperature and the initial temperature.
- ΔT = final temperature - inital temperature
The aluminum block was heated from 23.0 °C to 73.5 °C.
- ΔT= 73.5 °C - 23.0 °C = 50.5 °C
Now we know all three variables and can substitute them into the formula.
- m= 225 g
- c= 0.897 J/g° C
- ΔT= 50.5 °C
Multiply the first two numbers. The units of grams cancel.
Multiply again. This time, the units of degrees Celsius cancel.
The answer asks for the energy in kilojoules, so we must convert our answer. Remember that 1 kilojoule contains 1000 joules.
Multiply by the answer we found in Joules.
The original values of mass, temperature, and specific heat all have 3 significant figures, so our answer must have the same. For the number we found, that is the tneths place. The 9 in the hundredth place tells us to round the 1 up to a 2.
Approximately <u>10.2 kilojoules</u> of energy would be required.
Answer:
A. a rotten potato gives all of bad smell
Explanation:
B,C,D are all physical changes because we can reverse them back.we can cool the water back to make ice. if the wind passes again we can randomly get the same cloud shape in c. and in d we can make that statue again. but in A can we reverse the rotting process ? ( the enzyme reaction) no we cant because it is a chemical reaction it gives a bad smell because of the chemical changes occuring in it.
hope this helps
Answer:
Bohr model A
Explanation:
It has more valance electrons therefore has more interaction between the atoms and has more electronegativity.
Answer:
c is the answer then check it out
Answer:
63.05% of MgCO3.3H2O by mass
Explanation:
<em>of MgCO3.3H2O in the mixture?</em>
The difference in masses after heating the mixture = Mass of water. With the mass of water we can find its moles and the moles and mass of MgCO3.3H2O to find the mass percent as follows:
<em>Mass water:</em>
3.883g - 2.927g = 0.956g water
<em>Moles water -18.01g/mol-</em>
0.956g water * (1mol/18.01g) = 0.05308 moles H2O.
<em>Moles MgCO3.3H2O:</em>
0.05308 moles H2O * (1mol MgCO3.3H2O / 3mol H2O) =
0.01769 moles MgCO3.3H2O
<em>Mass MgCO3.3H2O -Molar mass: 138.3597g/mol-</em>
0.01769 moles MgCO3.3H2O * (138.3597g/mol) = 2.448g MgCO3.3H2O
<em>Mass percent:</em>
2.448g MgCO3.3H2O / 3.883g Mixture * 100 =
<h3>63.05% of MgCO3.3H2O by mass</h3>
