Friction occurs when two surfaces come into contact. Excess friction hinders movement, and it wastes energy. Friction refers to a force that opposes motion. It is important because it is applied in almost all life processes.
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Ninety nine percent of the atmosphere is composed of oxygen and nitrogen! The atmosphere is composed of 78% nitrogen and 21% oxygen!
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Answer:
The empirical formula is Li2CO3
Explanation:
Step 1: Data given
Suppose the mass of the compound = 100 grams
The compound contains :
18.7% Li = 18.7 grams of Li
16.3 % C = 16.3 grams of C
65.0% O = 65.0 grams of O
Total = 100%
Molar mass of Li = 6.94 g/mol
Molar mass of C = 12.01 g/mol
Molar mass of O = 16 g/mol
Step 2: Calculate moles
Moles = Mass / molar mass
Moles Li = 18.7 grams / 6.94 g/mol = 2.65 moles
Moles C = 16.3 grams / 12.01 = 1.36 moles
Moles O = 65.0 grams / 16.0 g/mol = 4.06 moles
Step 3: Calculate the mol ratio
We divide by the smallest number of moles
Li: 2.65/1.36 ≈ 2
C: 1.36/1.36 = 1
O: 4.06/1.36 ≈ 3
The empirical formula is Li2CO3
14. a. Acidic
15. b. Weaker
16. d. Dilute and weak
Explanation:
14. Which type of the solution is one with the pH of 3?
Solution with pH from 1 to 7 are acidic, equal to 7 is neutral and from 7 to 14 basic. The solution with the pH equal to 3 is <u>acidic</u>.
15. The smaller the value of the base dissociation constant (Kb), the <u>weaker</u> the base.
The dissociation reaction of a base (B) is:
B + H₂O → BH⁺ + OH⁻
Kb is defined as:
Kb = ( [BH⁺] × [OH⁻] ) / ( [B] × [H₂O] )
The potency of the base depends on the concentration of the hydroxide ion [OH⁻], so if the Kb ratio is small it means that the concentration of hydroxide ion is smaller so the base will be <u>weaker</u>.
16. A 0.39 M solution of an acid that ionizes only slightly in solution would be termed <u>dilute and weak</u>.
The acid is weak because is only slightly ionizing in solution. The therm diluted is a little bit arbitrarily because we ask yourself "diluted in respect with what"? I would characterize the acid to be diluted at a concentration of 1 M and concentrated at a concentration of 10 M.
Learn more about:
pH
brainly.com/question/1402522
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Answer:
5.2 ×10^-4 moles
Explanation:
Equation of reaction:
5C2O4^2- + 2MnO4^- +. 6H^+. ----------> 10CO2. +. 8H2O. + 2Mn^2+
From the information provided in the question:
Volume of potassium permanganate= 34.88ml
Concentration of potassium permanganate= 0.015M
Amount potassium permanganate= 0.015 × 34.88/1000= 5.2 ×10^-4 moles
