Answer:
A. 1.377 g
B. 16.5%
Explanation:
To find the water loss, subtract the salt and crucible mass from the hydrate and crucible mass
21.018 - 19.641 = 1.377
To find the water mass percentage, divide the empty crucible mass by the mass of the hydrate and crucible. Then, subtract that number from 1.
17.556 ÷ 21.018 = 0.835284
1 - 0.835284 = 0.164716
If you want to add an extra step, multiply this number by 100 to get the percentage.
0.164716 x 100 = 16.4716
Answer:
Percentage Yield = 56.9% (to 3 significant figures)
Explanation:
Firstly you need to calculate the amount of moles of Na used. Moles = Mass/Mr, so moles of Na = 1.72x10^-3/23. This gets you 7.47826087x10^-5 moles.
The mole ratio of Na:Na2O is 2:1 so the moles of Na2O will be the moles of Na divided by 2. This gets you 3.739130435x10^-5 moles.
Mass = Moles x Mr
The Mr of Na2O = 62
Mass = 3.739130435x10^-5 x 62 = 2.31826087x10^-3g
Percentage Yield = (Actual Yield / Theoretical Yield) x 100
Percentage Yield = (1.32x10^-3 / 2.31826087x10^-3) x 100
Percentage Yield = 56.93923481%
Percentage Yield = 56.9% (to 3 significant figures)
Answer:
There are 0.0305 calories in 0.128 joules
Explanation:
Given that,
Heat absorbed, Q = 0.128 J
We need to find the heat energy absorbed in calories.
We know that the relation between joules and calories is as follows :
1 calorie = 4.184 J
1 J = (1/4.184) J
So,
So, there are 0.0305 calories in 0.128 joules
Answer:
B one mole of carbon is lighter than one mole of magnesium
Answer:
Explanation:Artificial selection is distinct from natural selection in that it describes selection applied by humans in order to produce genetic change. When artificial selection is imposed, the trait or traits being selected are known, whereas with natural selection they have to be inferred. In most circumstances and unless otherwise qualified, directional selection is applied, i.e., only high-scoring individuals are favored for a quantitative trait. Artificial selection is the basic method of genetic improvement programs for crop plants or livestock (see Selective Breeding). It is also used as a tool in the laboratory to investigate the genetic properties of a trait in a species or population, for example, the magnitude of genetic variance or heritability, the possible duration of and limits to selection, and the correlations among traits, including with fitness.
