how do you separate a heterogenous mixture that contains powdered sulfur, pebbles, powdered iron, sand, and magnesium sulfate??

The concentration of Rn−222 in the basement of a house is 1.45 × 10−6 mol/L. Assume the air remains static and calculate the con

bonufazy [111]

Answer: The concentration of radon after the given time is $3.83\times 10^{-30}mol/L$

Explanation:

All the radioactive reactions follows first order kinetics.

The equation used to calculate half life for first order kinetics:

$t_{1/2}=\frac{0.693}{k}$

We are given:

$t_{1/2}=3.82days$

Putting values in above equation, we get:

$k=\frac{0.693}{3.82}=0.181days^{-1}$

Rate law expression for first order kinetics is given by the equation:

$k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}$

where,

k = rate constant = $0.181days^{-1}$

t = time taken for decay process = 3.00 days

$[A_o]$ = initial amount of the reactant = $1.45\times 10^{-6}mol/L$

[A] = amount left after decay process = ?

Putting values in above equation, we get:

$0.181days^{-1}=\frac{2.303}{3.00days}\log\frac{1.45\times 10^{-6}}{[A]}$

$[A]=3.83\times 10^{-30}mol/L$

Hence, the concentration of radon after the given time is $3.83\times 10^{-30}mol/L$

7 0

3 years ago

Why does magnesium oxide have a high melting point?

Mandarinka [93]

Magnesium oxide is an ionic compound ( because it consists of a metal and a non-metal)

In ionic compounds, electrons from the outer shell exchange between the atoms so that they each get a full outer shell. Once these electrons are exchange, the atoms will become ions. One ion will have a positive charge, and the other ion will have a negative charge. The positive and negative ions then bond strongly together in a lattice structure, due to the electrostatic forces of attraction.

These electrostatic forces of attraction are very strong and require a lot of energy to break, as such the compound will have a high melting point.

__________________________________________

Now lets look at the ionic bonding between magnesium and oxygen:

In the outer shell of Magnesium, there are 2 electrons.

In the outer shell Oxygen, there are 6 electrons.

Magnesium gives it's two electrons to Oxygen, so that the Oxygen now has a full outer shell of 8 electrons. However, since Oxygen gained two electrons, it will form a negatively charged ion with a charge of -2.

Since Magnesium lost the two electrons, it's second shell (which has 8 eletrons) now becomes the outer shell. So Magnesium also now has a full outer shell. But since it has lost two electrons, it becomes a positively charged ion with a charge of + 2.

The positive Magnesium ion and negative Oxygen ion and now strongly attracted to each other, and form a strong ionic compound (magnesium oxide) with a lattice structure.

The electrostatic forces of attraction between the positive Magnesium and negative Oxygen are so strong that a lot of heat and energy are needed to break them.

Therefore magnesium oxide has a high melting point.

5 0

2 years ago

Would you expect two electrons to attract or repel each other?

Fittoniya [83]

Repel because opposites only attract

8 0

3 years ago

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3

IceJOKER [234]

Answer:

1. The balanced equation is given below:

C4H6O3 + H2O → 2C2H4O2

The coefficients are: 1, 1, 2

Explanation:

C4H6O3 + H2O → C2H4O2

The above equation can be balanced as follow:

There are 4 atoms of C on the left side and 2 atoms on the right side. It can be balance by putting 2 in front of C2H4 O2 as shown below:

C4H6O3 + H2O → 2C2H4O2

Now, the equation is balanced as the number of atoms of the different elements present on both sides of the equation are equal.

The coefficients are: 1, 1, 2

5 0

3 years ago

Example of POTENTIAL ENERGY: and Example of KINETIC ENERGY:

Degger [83]

Potential : a yoyo before it’s been released
Kinetic : skateboarding

4 0

3 years ago

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