Answer:
the newspaper one is a chemical change because the chemicals in the paper have reacted with something and turned a different color. the wax one is a physical change because it is a change in the phase of matter, which is always a physical change (still the same substance chemically)
<h3>
Answer:</h3>
1379.4 Joules
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Explanation:</h3>
- The quantity of heat is calculated multiplying the mass of a substance by heat capacity and the change in temperature.
Therefore;
Quantity of heat = Mass × specific heat capacity × Change in temperature
Q = mcΔT
In this case;
The substance dissolved in water gained heat while water lost heat energy.
Thus, Heat gained by the substance = heat lost by water
Heat associated with the water
Mass of water = 75 g
Change in temperature = 4.4°C
Specific heat capacity = 4.18 J/g·⁰C
Heat = mcΔT
= 75 g × 4.18 J/g·⁰C × 4.4 °C
=1379.4 Joules
It’s easy, if the PH of any acidic solution = -Log[H+], where [H+] is hydrogen ion concentration, multiply each term by (-1) then raise each term as a power to (10), so it will become like this:-
[H+] = 10^(-PH)
Answer:
His results will be skewed because there was more water than stock solution. Which would cause the percentage solution to be less than 50% therefore the density would be less than the actual value.
Explanation:
The solution will have percentage less than that of 50%. Therefore the density would be less than the actual value.
Suppose there should be 50 mL of the solution, and he added 60 mL. So 10 mL of the solution is added more.
Suppose the mass of the solute is m.
Originally, the density is = 
Now after adding extra 10 mL , the density becomes 
.
Therefore, 
So the density decreases when we add more solution.
Answer:
Thus,there are 0.2 mole in 8 g of calcium.
