Answer:
Explanation:
Oxygen is one of the most abundant elements on this planet. Our atmosphere is 21% free elemental oxygen. Oxygen is also extensively combined in compounds in the earths crust, such as water (89%) and in mineral oxides. Even the human body is 65% oxygen by mass.
Free elemental oxygen occurs naturally as a gas in the form of diatomic molecules, O2 (g). Oxygen exhibits many unique physical and chemical properties. For example, oxygen is a colorless and odorless gas, with a density greater than that of air, and a very low solubility in water. In fact, the latter two properties greatly facilitate the collection of oxygen in this lab. Among the unique chemical properties of oxygen are its ability to support respiration in plants and animals, and its ability to support combustion.
In this lab, oxygen will be generated as a product of the decomposition of hydrogen peroxide. A catalyst is used to speed up the rate of the decomposition reaction, which would otherwise be too slow to use as a source of oxygen. The catalyst does not get consumed by the reaction, and can be collected for re-use once the reaction is complete. The particular catalyst used in this lab is manganese(IV) oxide.
Answer:
While both handwashing and hand sanitizing are good hygiene practices, each has its ... The difference between soaps and detergents lies in their ingredients and how they are made. ... Before handling clean equipment and serving utensils;; When changing tasks and switching ... Do not wash or rub it off on your clothes.
Explanation:
Answer:
1.634 molL-1
Explanation:
The mol ration between NH3 and HCl is 1 : 1
Using Ca Va / Cb Vb = Na / Nb where a = acid and b = base
Na = 1
Nb = 1
Ca = 0.208 molL-1
Cb = ?
Va = 19.64 mL
Vb = 25.00mL
Solving for Cb
Cb = Ca Va / Vb
Cb = 0.208 * 19.64 / 25.0
Cb = 0.1634 molL-1 (Concentration of diluted ammonia solution)
Using the dilution equation;
C1V1 = C2V2
Initial Concentration, C1 = ?
Initial Volume, V1 = 25.00 mL
Final Volume, V2 = 250 mL
Final Concentration, C2 = 0.1634 molL-1
Solving for C1;
C1 = C2 * V2 / V1
C1 = 0.1634 * 250 / 25.00
C1 = 1.634 molL-1
According to the reversible reaction equation:
2Hi(g) ↔ H2(g) + i2(g)
and when Keq is the concentration of the products / the concentration of the reactants.
Keq = [H2][i2]/[Hi]^2
when we have Keq = 1.67 x 10^-2
[H2] = 2.44 x 10^-3
[i2] = 7.18 x 10^-5
so, by substitution:
1.67 x 10^-2 = (2.44 x 10^-3)*(7.18x10^-5)/[Hi]^2
∴[Hi] = 0.0033 M
Answer:
amphibians
Explanation:
because frogs have to stay in water while tadpole then they come to land
