Answer:
Kindly, see the attached image.
Explanation:
As clear in the attached image:
- It represents the cooling curve of water.
- It starts from 20°C, the water exists in the liquid phase.
- With time the temperature is decreased, reaching 0°C, the two phases (liquid and solid) are co-exist.
- Then, with further cooling and under 0°C reaching -20°C, all the water are exist in the solid phase (Ice).
<em>Kindly, see the attached image that clarify the cooling graph of water as it passes from 20°C to –20°C. </em>
<em />
Answer:
42.3%
Explanation:
By the reaction given the stoichiometry between MnO₄⁻ and Fe⁺² is 1 mol of MnO₄⁻ to 5 moles of Fe⁺². When KMnO₄ dissolves, it forms the same amount of K⁺ and MnO₄⁻ (1:1:1), so the number of moles of MnO₄⁻ used is:
n = Volume*concentration
n = 0.0216 L * 0.102 mol/L
n = 2.20x10⁻³ mol
1 mol of MnO₄⁻ -------------------- 5 moles of Fe⁺
2.20x10⁻³ mol ---------------------- x
By a simple direct three rule
x = 0.011 mole
The molar mass of iron is 55.8 g/mol. The mass is the molar mass multiplied by the number of moles, thus:
m = 55.8*0.011
m = 0.614 g
Then, the percent of iron in the ore is:
(mass of iron/ mass of ore) *100%
(0.614/1.45)*100%
42.3%
Explanation:
Fractional distillation is used to separate crude oil into simpler, more useful mixtures . This method can be used because different hydrocarbons have different boiling points
Hope this help u
Answer: This reaction is called as Chemiluminescence. A type of reaction in which light is produced due to chemical reaction. While in case of Phosphorescence and Fluorescence light is emitted due to absorption of photons.
Explanation: i looked the answer up but your welcomee ❤
Answer:
The correct option is B
Explanation:
The number of valence electron(s) increases across the period and thus influences the direction of periodic trend of electronegativity, electron affinity and ionization energy across the period. Thus, making option B the answer.
It should be noted that option A is wrong because elements in the same period generally have the same number of electron shells and thus the distance of this shells from the nucleus remains the same throughout the same period and thus option C is also wrong. Option D is wrong because the periodic trends have to do with chemical reactions which actually involves electrons and not protons.
