Answer:
When the electron changes levels, it decreases energy and the atom emits photons. The photon is emitted with the electron moving from a higher energy level to a lower energy level. The energy of the photon is the exact energy that is lost by the electron moving to its lower energy level.
Explanation:
Answer:
1.1 liters
1.2 liters
1.5 liters
Explanation:
Precision in data refers to how close the experimental values of an experiment are to one another irrespective of the true or accepted value. In other words, a set of values are said to be PRECISE if they are close to one another.
In this case, data was collected after conducting an experiment about the amount, in liters, of water a specific plant needs per month. However, according to the set of experimental values provided, only 1.1 litres, 1.2litres and 1.5litres are close to one another and, hence, are said to be PRECISE even if they are not close to the accepted value of 6litres.
Answer : The correct option is, 
Explanation :
- Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. That means, the loss of electrons takes place.
Or we can say that, oxidation reaction occurs when a reactant losses electrons in the reaction.
- Reduction reaction : It is defined as the reaction in which a substance gains electrons. That means, the gain of electrons takes place.
Or we can say that, reduction reaction occurs when a reactant gains electrons in the reaction.
According to the electrochemical series, most likely to be reduced because
Hence, the ion most likely to be reduced is .
Answer:
693K
Explanation:
The enthalpy change in the iron is 3690J
We now apply the formula for enthalpy change which is ΔH=mC∅ where ∅ is the temperature change, m the mass of the substance, and C the specific heat capacity for the substance.
ΔH in this case is 3690J.
Therefore 3690J=21.5g×0.449J/g.K×∅
as we are looking for ∅, we make it the subject of the formula.
∅=3690J/(21.5g×0.44J/g)
∅=390
Temperature=30°C +390
=420°+273
=693K
Answer:
3.861x10⁻⁹ mol Pb⁺²
Explanation:
We can <u>define ppm as mg of Pb²⁺ per liter of water</u>.
We<u> calculate the mass of lead ion in 100 mL of water</u>:
- 100.0 mL ⇒ 100.0 / 1000 = 0.100 L
- 0.100 L * 0.0080 ppm = 8x10⁻⁴ mg Pb⁺²
Now we <u>convert mass of lead to moles</u>, using its molar mass:
- 8x10⁻⁴ mg ⇒ 8x10⁻⁴ / 1000 = 8x10⁻⁷ g
- 8x10⁻⁷ g Pb²⁺ ÷ 207.2 g/mol = 3.861x10⁻⁹ mol Pb⁺²
