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3 years ago

Calculate the average atomic mass of antimony

Chemistry

1 answer:

densk [106]3 years ago

4 0

Answer:

Wow, now this one is a hard one, took me quite a while to figure it out but here it is

The abundances of the two isotopes is:

Antimony-121 = 57.2%

Antimony-123 = 42.8%

Explanation:

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A 0.5895-g sample of impure magnesium hydroxide is dissolved in 100.0 mL of 0.2050 M HCl solution. The excess acid then needs 19

Zepler [3.9K]

Answer:

91.38 %

Explanation:

First we use the following formula to calculate the number of moles of HCl and NaOH contained in the solutions:

molar concentration = number of moles / solution volume

number of moles = molar concentration × solution volume

number of moles of HCl = 0.2050 × 100 = 20.5 mmoles

number of moles of NaOH = 0.1020 × 19.85 = 2.02 mmoles

reaction between NaOH and HCl:

NaOH + HCl → NaCl + H₂O

If 2.02 mmoles of NaOH were used for neutralization of HCl left from the reaction, which are 2.02 mmoles of HCl, it means that the HCl reacted with Mg(OH)₂:

20.5 - 2.02 = 18.48 mmoles of HCl

2 HCl + Mg(OH)₂ = MgCl₂ + 2 H₂O

From the chemical reaction we devise the following reasoning:

if 2 mmoles of HCl react with 1 mmole of Mg(OH)₂

then 18.48 mmoles HCl react with X mmoles of Mg(OH)₂

X = (18.48 × 1) / 2 = 9.24 mmoles of Mg(OH)₂

now the mass of Mg(OH)₂:

mass = number of moles × molecular weight

mass of Mg(OH)₂ = 9.24 × 58.3 = 538.7 mg = 0.5387 g

Now the percent by mass of magnesium hydroxide Mg(OH)₂ in the impure sample (purity):

purity = (mass of pure Mg(OH)₂ / mass of impure sample) × 100

purity = (0.5387 / 0.5895) × 100

purity = 91.38 %

7 0

3 years ago

Which formula represents the compound commonly known as phosphine?

sineoko [7]

Your answer should be c ph3

3 0

3 years ago

Read 2 more answers

Calculate the percentage by mass of cerium in cerium carbonate

levacccp [35]

Answer:

60.88%

Explanation:

The formula for cerium carbonate is Ce₂(CO₃)₃.

Let's assume we have 1 mol of cerium carbonate. The total mass would be equal to the molar mass of Ce₂(CO₃)₃, 460.25 g/mol.

Out of those 460.25 g, the mass corresponding to cerium would be:

2 * Molar mass of Ce = 2 * 140.11 g/mol = 280.22 g

Now we can calculate the percentage by mass of cerium:

% mass = 280.22 / 460.25 * 100% = 60.88%

5 0

2 years ago

Which root word of the binary ionic compound ends with -ide

kondor19780726 [428]

Answer: C. The non metal

Explanation:-

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

The nomenclature of ionic compounds is given by:

1. Positive ion or metal is written first.

2. The negative ion or non metal is written next and a suffix is added at the end of the negative ion. The suffix written is '-ide'.

For example: $CsBr$ , cesium is metal having an oxidation state of +1 called as $Cs^{+}$ cation and bromine $Br^{-}$ is an anion with oxidation state of -1. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral $CsBr$ called as cesium bromide.

4 0

3 years ago

What is a way to show photosythsis in a model

matrenka [14]

It's quite simple...

You have to show a plant and draw and arrow coming towards the leaf to represent the intake of carbon dioxide and an arrow drawn from the leaf into the surroundings to represent the oxygen being released after the photosynthesis. You can also draw a sun at one corner and show the sun rays reaching the plant as well as the water being taken in by the plant through the roots from the soil.

Hope it helps!!!

3 0

3 years ago