The model most likely represents a reaction which
Select one:
a. takes place when atoms combine
b. takes place when atoms become inactive
c. does not produce energy in the sun
d. does not produce energy in nuclear power plants
Answer: b: takes place when atoms become inactive
Explanation: the model described above is a nuclear fission reaction, a reasonably controlled reaction that releases energy and is employed in nuclear power plants. In these reactions one Atom is split into two lighter ones and there's a resultant release of energy in the process. The original Atom becomes depleted (inactive) as is the case with Uranium 235.
This reaction is opposed to fusion reactions that occur in nature e.g. the sun, and are basically uncontrollable — involving the combination of two atoms into one.
Why can't we change the subscripts in balancing chemical equations?
1 m
1.000 mm
= 0.025 mm
1.000 mm
O 25.000 mm; because 25 m x = 25,000 mm
1 m
25.000 mm; because 25 m X
100 mm
= 2500 mm
1 m
O 0.025 mm; because 25 m x
1 m
100 mm
= 0.25 mm
Answer:
25000 mm: because 25 m × 1000 mm /1 m = 25000 mm
Explanation:
We can convert 25 m to millimetre (mm) by doing the following:
Recall:
1 m = 1000 mm
Therefore,
25 m = 25 m × 1000 mm /1 m = 25000 mm
25 m = 25000 mm
Thus, 25 m is equivalent to 25000 mm
What is the molecular formula of the alcohol?
Answer:
Explanation:
For a compound as:
Let say your sample weighs 100 g, then you have
52 g of C
35 g of O
13 g of H
Now you need to calculate the moles in the sample:
moles of C = 52 / 12 = 4.3333
moles of O = 35 / 16 = 2.1875
moles of H = 13 / 1 = 13
Now you divide the moles by the least to have a proportion (2.1875):
moles of C = 4.3333 / 2.1875 = 2
moles of O = 2.1875 / 2.1875 = 1
moles of H = 13 / 2.1875 = 6
So the molecule proportion of atoms is C:H:O = 2:6:1
Now to find x you have to calculate the MM:
MM = 12 * 2x + 1 * 6x + 16 * x = 46x
For x = 1 => MM = 46(1) = 46
For x = 2 => MM = 46(2) = 92
Since the MM is between 30 and 80, x = 1
B. 15 protons, 15 electrons
C. 60 protons, 30 electrons
D. 30 protons, 0 electrons
b. lead mixed with heavier substances
c. lead mixed with lighter substances
Answer:
The correct answer is option c.
Explanation:
Density is defined as mass present in unit volume of the substance.
Given that density of pure lead is more than that of the sample.
Density of lead =
Density of sample =
Since, we know that density is directly linked to mass of the substance. So with decrease in density of substance indicates that mass present in unit volume of the substance has also decreased.
The reason behind the less density of sample from lead was that, that it was made up lead and other light substance.