Answer:
It is the third one, 2 atoms of Aluminum and 3 atoms of Oxygen
1. The burning of propane creates different substances: propane and oxygen combine to create water and carbon dioxide:
<span><span>C<span>3</span>H<span>8</span></span> + 5 <span>O<span>2</span></span> becomes 3 CO2 + 4 <span>H<span>2</span>O</span> + heat
</span><span>
2. When NaCl melts, it is changing state, but it is still the same NaCl.
3. When gaseous CO2 deposits it is changing state, but it is still the same CO2.
4. When (presumably liquid) water solidifies, it is changing state, but it is still the same water.
So the answer is 1.</span>
Answer:
159.609 g/mol
Explanation:
According to the CuSO4.5H2O (k) heat CuSO4 (k) + 5 H2O (g) equation, the crystal water amount of copper sulfate and its rough formula will be calculated.
Weight of copper sulfate containing crystal water = m1 = 249.62… g
Weight of copper sulfate without crystal water weighed = m2 = 159.62 g
Accordingly, calculate the x and y values in the molecular formula of copper sulfate (xCuSO4.yH2O).
Answer:
i = 2.79
Explanation:
The excersise talks about the colligative property, freezing point depression.
Formula to calculate the freezing point of a solution is:
Freezing point of pure solvent - Freezing point of solution = m . Kf . i
Let's replace data given. (i = Van't Hoff factor, numbers of ions dissolved in solution)
48.1°C - 44°C = 0.15 m . 9.78°C/m . i
4.1°C / (0.15 m . 9.78°C/m) = i
i = 2.79
In this case, numbers of ions dissolved can decrease the freezing point of a solution, which is always lower than pure solvent.
