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2 years ago

What elements did the first periodic table stop on?

Chemistry

1 answer:

gtnhenbr [62]2 years ago

5 0

Answer:

Bismuth

Explanation:

In 1869 Mendeleev published his first Periodic System ending with Bismuth.

In 1871 he updated his system to end with Uranium.

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As the ph approaches 0, what happens to the concentration of h3o+ ions?

natta225 [31]

We know that

pH = -log[H+]

the pH value falls in between 0- 7 for acids

As the pH value increases the concentration of [H+] increases.

similarly as the value of pH approaches 0, the concentration of H+ increases

The solution said to become more acidic

Also

[H+] X [OH-] = 10^-14

Thus pH + pOH = 14

hence the concentration of OH- decreases as the pH approaches zero

6 0

3 years ago

What is the mass of sodium (Na) in 50 grams of table salt (NaCl)? Show your work.

Margaret [11]

Answer:

19 g

Explanation:

Data Given:

Sodium Chloride (table salt) = 50 g

Amount of sodium (Na) = ?

Solution:

Molecular weight calculation:

NaCl = 23 + 35.5

NaCl = 58.5 g/mol

Mass contributed by Sodium = 23 g

calculate the mole percent composition of sodium (Na) in sodium Chloride.

Since the percentage of compound is 100

So,

Percent of sodium (Na) = 23 / 58.5 x 100

Percent of sodium (Na) = 39.3 %

It means that for ever gram of sodium chloride there is 0.393 g of Na is present.

So,

for the 50 grams of table salt (NaCl) the mass of Na will be

mass of sodium (Na) = 0.393 x 50 g

mass of sodium (Na) = 19 g

8 0

3 years ago

Read 2 more answers

What is the mass of a 0.23 L substance, if it has density of 1.90 g/mL?

jolli1 [7]

Answer:

437 g

Explanation:

as mass = density × volume

8 0

3 years ago

Pharmacy technician measures the mass of a pill. The mass of one pill is

Galina-37 [17]

The mass of 100 pills would be 78000 mg and 0.078 kilograms.

Hope this helps you :)

8 0

3 years ago

Read 2 more answers

One way of obtaining pure sodium carbonate is through the decomposition of the mineral trona, Na3(CO3)(HCO3)·2H2O. 2Na3(CO3)(HCO

zhenek [66]

Percentage yield = (actual yield / theoretical yield) x 100%

The balanced equation for the decomposition is,
2Na₃(CO₃)(HCO₃)·2H₂O(s) → 3Na₂CO₃(s) + CO₂(g) + 5H₂<span>O(g)

The stoichiometric ratio between </span>Na₃(CO₃)(HCO₃)·2H₂O(s) and Na₂CO₃(s) is 2 : 3

The decomposed mass of Na₃(CO₃)(HCO₃)·2H₂O(s) = 1000 kg
= 1000 x 10³ g

Molar mass of Na₃(CO₃)(HCO₃)·2H₂O(s) = 226 g mol⁻¹
moles of Na₃(CO₃)(HCO₃)·2H₂O(s) = mass / molar mass
= 1000 x 10³ g / 226 g mol⁻¹
= 4424.78 mol

Hence, moles of Na₂CO₃ formed = 4424.78 mol x $\frac{3}{2}$
= 6637.17 mol

Molar mass of Na₂CO₃ = 106 g mol⁻¹

Hence, mass of Na₂CO₃ = 6637.17 mol x 106 g mol⁻¹
= 703540.02 g
= 703.540 kg

Hence, the theoretical yield of Na₂CO₃ = 703.540 kg
Actual yield of Na₂CO₃ = 650 kg

Percentage yield = (650 kg / 703.540 kg) x 100%
= 92.34%

7 0

3 years ago