According to the question, the determined melting point of the compound is 112.5-113.0oC. When the solidified compound was retried, the melting point was found to be 133.6-154.5oC. This greater range higher than 112°C is caused by reusing samples leads to errors.
A pure sample is known by its sharp melting point. A pure sample does not melt over a large range. We can see this in the predetermined melting points of the pure sample(112.5-113.0oC).
However, reusing a sample introduces errors because the pure sample may become contaminated leading to a larger and higher range of melting point (133.6-154.5oC) which is far above 112°C.
Learn more: brainly.com/question/5325004
Answer:
26.74g
Explanation:
The equation of the reaction is;
SIO₂ + 3C --> SiC +2CO
From the balanced equation, the relationship between SiC and C is;
3 mol of C produces 1 mol of SiC
Converting mol to mass using; Mass = moles * Molar mass
Mass of SiC = 1 mol * 40.11 g/mol = 40.11g
This means;
3 mol of C produces 40.11g of SiC
2 mol of C produces xg of SiC
3 = 40.11
2 = x
x = 2 * 40.11 / 3 = 26.74g
Answer:
B
Explanation:
Molarity = 0.010M
Volume = 2.5L
Applying mole-concept,
0.010mole = 1L
X mole = 2.5L
X = (0.010 × 2.5) / 1
X = 0.025moles
0.025moles is present in 2.5L of NaOH solution.
Molar mass of NaOH = (23 + 16 + 1) = 40g/mol
Number of moles = mass / molar mass
Mass = number of moles × molar mass
Mass = 0.025 × 40
Mass = 1g
1g is present in 2.5L of NaOH solution
Answer:
<em>The solution with the lowest pH is 0.1 M HCl.</em>
Explanation:
Since the three solutions have the same concentration (0,1M) it is only necessary to look at the pKa of each solution.
Also, knowing that a higher pKa means a lower Ka, because pKa = -Log (Ka). Thus, a lower Ka means a lower concentration of protons with a higher pH ( pH = -Log [H+].
The HCl doesn't have a pKa because is a strong acid that dissociates completely. Therefore, this solution produces a lower pH. Looking at the pKa of acetic acid and formic acid solutions, the second with the lowest pH is the formic acid solutions and the higher pH is for the acetic acid solution.
