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2 years ago

Convert 1.72 moles of magnesium carbonate to formula units

1 answer:

8 0

One mole any substance contains 6.022 ₓ 10²³ particles called Avogadro's Number.

The relation between moles and number of particles is given as,

# of particles = moles ₓ Avogadro's number

In our case the particles are formula units of MgCO₃. So, 1 mole of MgCO₃ contain 6.022 ₓ 10²³ formula units, then the number of formula units in 1.72 moles are calculated as,

# of formula units = 1.72 mol ₓ 6.022 ₓ 10²³ formula units / mol

# of formula units = 1.035 ₓ 10²⁴ Formula Units

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Pesticide concentrations in the Rhine River between Germany and France between 1969 and 1975 averaged 0.55 mg/L of hexachloroben

sertanlavr [38]

Answer:

1.93×10⁻³ mmoles/L of C₆Cl₆; 1.58×10⁻⁴ mmoles/L of C₁₂H₈Cl₆O; 3.51×10⁻³ mmoles/L of C₆H₆Cl₆

Explanation:

We have to find out the molar mass of each pesticide to calculate the moles, and then the milimoles

C₆Cl₆ → 12. 6 + 35.45 .6 = 284.7 g/m

C₁₂H₈Cl₆O → 12 . 12 + 8.1 + 35.45 .6 + 16 = 380.7 g/m

C₆H₆Cl₆ → 12.6 + 6.1 + 35.45 .6 = 290,7 g/m

Let's convert mg to g (/1000)

0.55 mg / 1000 = 5.5×10⁻⁴ g

0.060 mg / 1000 = 6×10⁻⁵ g

1.02 mg / 1000 = 1.02×10⁻³ g

Now we can know the moles (mass / molar mass)

5.5×10⁻⁴ g / 284.7 g/m = 1.93×10⁻⁶ moles of C₆Cl₆

6×10⁻⁵ g / 380.7 g/m = 1.58×10⁻⁷ moles of C₁₂H₈Cl₆O

1.02×10⁻³ g / 290,7 g/m = 3.51×10⁻⁶ moles of C₆H₆Cl₆

Milimoles = Mol . 1000

1.93×10⁻⁶ . 1000 = 1.93×10⁻³ mmoles of C₆Cl₆

1.58×10⁻⁷ . 1000 = 1.58×10⁻⁴ mmoles of C₁₂H₈Cl₆O

3.51×10⁻⁶ . 1000 = 3.51×10⁻³ mmoles of C₆H₆Cl₆

6 0

2 years ago

SEP Use Models Why does the number of electrons in each principal energy shell increase as the number of the shell increases?

zlopas [31]

Answer:

See explanation

Explanation:

The number of electrons in each principal energy shell increases as the number of shells increases because more electronic orbitals become available to accommodate the electrons.

For instance, the n= 2 level only accommodates eight electrons in the s and p orbitals whereas the n=3 level accommodates 18 electrons in s, p and d orbitals respectively.

Each principal level accommodates 2n^2 electrons where n= the principal energy shell.

4 0

1 year ago

One hour of bicycle riding can require 500-900 kcal of energy, depending on the speed, the terrain, and the weight of the racer.

solniwko [45]

Answer:

145 hours

Explanation:

Since one hour of riding a bicycle takes up 505 kcal of energy. It is also stated that one gram of body fat is equal to 7.70 kcal. Also, it is given that 1 pound of body fat is equal to 454 g.

Hence;

1 Ib= 454 g

21 Ib= 21 × 454/1 = 9534 g

But

1g of body fat = 7.70kcal

9534 g of body fat = 9534 × 7.70 kcal/1 = 73411.8 kcal

If 505 kcal is lost in 1 hour

73411.8 kcal is lost in 73411.8 kcal × 1hour/505k cal = 145 hours

3 0

2 years ago

What impact would adding twice as much Na2 CO3 than required for stoichiometric quantities have on the quantity of product produ

IrinaK [193]

Answer:

There will be no observed impact of adding twice as much Na2CO3 on the product

Explanation:

Stoichiometry gives the relationship between reactants and products in terms of mass, mole and volume.

If we consider the stoichiometry of the reaction, we will discover that the reaction occurs in a 1:1 ratio. This implies that use of twice the amount of Na2CO3 will only lead to an excess of Na2CO3 making the other reactant the limiting reactant. Once the other reactant is used up, the reaction quenches.

Hence, use of twice as much Na2CO3 has no impact on the quantity of product produced.

5 0

2 years ago

A concentration cell is constructed using two Ni electrodes with Ni2+ concentrations of 1.0 M and 1.00 � 10�4 M in the two half-

Komok [63]

Answer: The cell potential of the cell is +0.118 V

Explanation:

The half reactions for the cell is:

Oxidation half reaction (anode): $Ni(s)\rightarrow Ni^{2+}+2e^-$