Answer:
0.005 mol
Explanation:
Moles is denoted by given mass divided by the molecular mass ,
Hence ,
n = w / m
n = moles ,
w = given mass ,
m = molecular mass .
From the question ,
w = given mass of Gold = 1.05 g ,
m = molecular mass of Gold = 197 g/mol
<u>Hence , moles can be calculated as -</u>
n = w / m
= 1.05 g / 197 g/mol = 0.005 mol
Answer:
The effects of supercritical CO2 (SC-CO2) on the microbiological, sensory (taste, odour, and colour), nutritional (vitamin C content), and physical (cloud, total acidity, pH, and °Brix) qualities of orange juice were studied. The CO2 treatment was performed in a 1 litre capacity double-walled reactor equipped with a magnetic stirring system. Freshly extracted orange juice was treated with supercritical CO2, pasteurised at 90°C, or left untreated. There were no significant differences in the sensory attributes and physical qualities between the CO2 treated juice and freshly extracted juice. The CO2 treated juice retained 88% of its vitamin C, while the pasteurised juice was notably different from the fresh juice and preserved only 57% of its vitamin C content. After 8 weeks of storage at 4°C, there was no microbial growth in the CO2 treated juice.
The general properties of Group 1 alkali metals are:
1. They form cations.
2. They are highly reactive.
3. They have a charge of +1.
4. They form ionic compounds.
5. When their oxides or hydroxides are reacted in water, they form alkalis i.e. bases.
6. They are usually soft in nature.
7. They have low densities.
Answer:
B is correct → since temperature can be measured confidently and the variations with temperature are greater ( then the errors in measuring time diminishes)
Explanation:
A is not correct → since the sugar cubes will be still surrounded by water at the temperature chosen regardless of the size of the glass, organising the data by size of the glass is not correct since the glass size does not affect in a significant way to the results ( it could affect the cooling rate of water due to the exposed surface , it but would be insignificant)
C is not correct → since the sugar cubes are approximately of the same size , putting 2 cubes or "n" cubes will not affect the time significantly since each cube is still surrounded by water at the same temperature and behaves independently from others , then each cube dissolves at the same time ( there would be small variations due to the different sizes of the cubes and the small variation due to the limited mass of water)
D is not correct → since the solubility of sugar in water is high , the amount left after the experiment would be very small ( thus the relative errors are high) and the sugar would be contaminated with water in the weighting operation, leading to more errors
B is correct → since temperature can be measured confidently and the variations with temperature are greater ( then the errors in measuring time diminishes)
