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3 years ago

The elements Lithium (Li), Boron (B), and Oxygen (O) are all in the same _________ on the periodic table.

Chemistry

1 answer:

AnnyKZ [126]3 years ago

7 0

Answer:

Period

Explanation:

If we ubicate te period one on the alkaline metals, we can see the lithium, so we go to the borans on te group AIII an we see Boron, move to the rigth on the same sense tou the group AVI we see the Oxygen, we can know that also for the electronic configuration Li:1s²2s¹ B:1s²2s²3p

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3 years ago

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H2CO3(aq) + H200 H30 (aq) + HCO3 (aq).

timofeeve [1]

Answer:

$K_a=\frac{[H_3O^+][HCO_3^-]}{[H_2CO_3]}$

Explanation:

Several rules should be followed to write any equilibrium expression properly. In the context of this problem, we're dealing with an aqueous equilibrium:

an equilibrium constant is, first of all, a fraction;
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Following the guidelines, we will omit liquid water and we will include all the other species in the constant. Each coefficient in the balanced equation is '1', so no powers required. Multiply the concentrations of the two products and divide by the concentration of carbonic acid:

$K_a=\frac{[H_3O^+][HCO_3^-]}{[H_2CO_3]}$

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3 years ago

What are the mole fraction and the mass percent of a solution made by dissolving 0.21 g KBr in 0.355 L water? (d = 1.00 g/mL.) m

IRISSAK [1]

Answer:

Mol fraction H2O = 0.99991

Mol fraction KBr = 0.00009

mass % KBr = 0.059 %

mass % H2O = 99.941 %

Explanation:

Step 1: Data given

Mass of KBr = 0.21 grams

Molar mass KBr = 119 g/mol

Volume of water = 355 mL

Density of water = 1.00 g/mL

Molar mass water = 18.02 g/mol

Step 2: Calculate mass water

Mass water = 355 mL * 1g /mL

Mass water = 355 grams

Step 3: Calculate moles water

Moles water = mass water / molar mass water

Moles water = 355 grams / 18.02 g/mol

Moles water = 19.7 moles

Step 4: Calculate moles KBr

Moles KBr = 0.21 grams / 119 g/mol

Moles KBr = 0.00176 moles

Step 5: Calculate total moles

Total moles = 19.7 moles + 0.00176 moles

Total moles = 19.70176 moles

Step 6: Calculate mol fraction

Mol fraction H2O = 19.7 moles / 19.70176 moles

Mol fraction H2O = 0.99991

Step 7: Calculate mol fraction KBr

Mol fraction KBr = 0.00176 / 19.70176

Mol fraction KBr = 0.00009

Step 6: Calculate mass %

mass % KBR = (0.21 grams / (0.21 + 355) grams) *100%

mass % KBr = 0.059 %

mass % H2O = (355 grams / 355.21 grams) *100%

mass % H2O = 99.941 %

8 0

3 years ago

Why is feo named using a roman numeral, iron (ii) oxide, whereas cao named without a roman numeral, calcium oxide?

Hitman42 [59]

<span>Answer: Some metals have the ability to form differently charged ions. For example, iron can form 2 + or 3 + ions. If you simply gave the name iron chloride, you would not know which charge the iron ion possessed. A Roman numeral is to indicate the charge of the iron. Iron ( II ) means the iron has a 2 + charge Iron ( III ) means that the iron has a 3 + charge So, iron ( II ) oxide would have a chemical formula of FeO . (The oxide ion has a 2 â’ charge to balance the 2 + of the iron to form a neutral compound.) Iron ( III ) oxide would have a chemical formula of Fe 2 O 3 (Here you need to find the common multiple of 6, so two iron ions with a 3 + charge will balance the charge of three oxide ions with a 2 + charge.)</span>

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3 years ago

In the titration of 50. 0 mL of 0. 400 M HCOOH with 0. 150 M LiOH, how many mL of LiOH are required to reach the equivalence poi

mart [117]

The volume of the 0.15 M LiOH solution required to react with 50 mL of 0.4 M HCOOH to the equivalence point is 133.3 mL

<h3>Balanced equation </h3>

HCOOH + LiOH —> HCOOLi + H₂O

From the balanced equation above,

The mole ratio of the acid, HCOOH (nA) = 1

The mole ratio of the base, LiOH (nB) = 1

<h3>How to determine the volume of LiOH </h3>

Molarity of acid, HCOOH (Ma) = 0.4 M
Volume of acid, HCOOH (Va) = 50 mL
Molarity of base, LiOH (Mb) = 0.15 M

Volume of base, LiOH (Vb) =?

MaVa / MbVb = nA / nB

(0.4 × 50) / (0.15 × Vb) = 1

20 / (0.15 × Vb) = 1

Cross multiply

0.15 × Vb = 20

Divide both side by 0.15

Vb = 20 / 0.15

Vb = 133.3 mL

Thus, the volume of the LiOH solution needed is 133.3 mL

Learn more about titration:

brainly.com/question/14356286

8 0

2 years ago