The sensitivity of electronic balance is 0.3 mg
Converting 0.3 mg to g:
g
So, the mass of a substance weighed on the balance can be measured accurately up to four decimal places.
Given the mass of sample is 1.2300 g. The number of significant figures in the measurement will be 5 because the balance can measure the mass of a sample accurately up to four decimal points, all the digits in the measurement will be significant.
Answer:
496 g of Fe₂O₃.
Explanation:
The balanced equation for the reaction is given below:
4Fe + 3O₂ —> 2Fe₂O₃
From the balanced equation above,
4 moles of Fe reacted to produce 2 moles of Fe₂O₃.
Therefore, 6.20 moles of Fe will react to produce = (6.20 × 2)/4 = 3.1 moles of Fe₂O₃
Finally, we shall determine the mass of 3.1 moles of Fe₂O₃. This can be obtained as follow:
Mole of Fe₂O₃ = 3.1 moles
Molar mass of Fe₂O₃ = (56 × 2) + (3×16)
= 112 + 48
= 160 g/mol
Mass of Fe₂O₃ =?
Mass = mole × molar mass
Mass of Fe₂O₃ = 3.1 × 160
Mass of Fe₂O₃ = 496 g
Therefore, 496 g of Fe₂O₃ were produced from the reaction.
Hello! So to answer your question all the answers can be found within the above chart provided. Simply compare and contrast the pH levels in which the indicators changed color.
So doing that we can conclude the followoing pertaining to our indicators. Bromothymol blue 5.3-7.3
Methyl yellow 2.4-4.3
Bromocresol green 3.3-5.3
Red cabbage extract 3.3-5.3
For your second question it is the exact same concept, but we can just look at our answer for the first question to conclude which indicator would be best used for those ph levels.
Comparing and contrasting we can see that the best indicator to use for observing PH changes around pH= 2 would be Methyl yellow,
for around pH=4 would be Bromocrescol green,
and for pH= 6 it would be Bromothymol blue.
If you have any other questions or would like further explanation just let me know! :)
Answer:
b
Explanation:
A pure substance has a constant composition and cannot be separated into simpler substances by physical means. There are two types of pure substances: elements and compounds.
Answer: Option (4) is the correct answer.
Explanation:
Activation energy is the minimum amount of energy required by the reactants to participate in the chemical reaction.
Therefore, reactant molecules whose energy is less than the activation energy are not able to participate in the reaction. Hence, a catalyst lowers the activation energy so that molecules with less energy can also participate in the reaction.
Thus, a catalyst is a specie that increases the reaction rate and has a lower activation energy.