Which of the following is a pure substance

Are my answers correct?

olga_2 [115]

Answer: yes

Explanation: its common sense

6 0

2 years ago

Why don't satellites in orbit fly into space?

Alex787 [66]

This is a question similar to one wrestled with by Newton himself, who didn't understand why the planets didn't fall into each other. The reason satellites don't fly into space is because they are being pulled towards the planet by the planet's gravity.

7 0

3 years ago

If the reaction N2 (g) + 3 H2 (g) --> 2 NH3 (g) has the concentrations 1.1 M for nitrogen, 0.75 M for hydrogen and 0.25 M fo

Luba_88 [7]

Answer: The value of $K_c$ is 0.136 and is reactant favored.

Explanation:

Equilibrium constant in terms of concentration is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as $K_{c}$

For the chemical reaction between carbon monoxide and hydrogen follows the equation:

$N_2(g)+3H_2(g)\rightleftharpoons 2NH_3(g)$

The expression for the $K_{c}$ is given as:

$K_{c}=\frac{[NH_3]^2}{[N_2][H_2]^3}$

We are given:

$[NH_3]=0.25M$

$[H_2]=0.75M$

$[N_2]=1.1M$

Putting values in above equation, we get:

$K_c=\frac{(0.25)^2}{1.1\times (0.75)^3}$

$K_c=0.135$

There are 3 conditions:

When $K_{c}>1$ ; the reaction is product favored.
When $K_{c}$ ; the reaction is reactant favored.
When $K_{c}=1$ ; the reaction is in equilibrium.

For the given reaction, the value of $K_c$ is less than 1. Thus, the reaction is reactant favored.

Hence, the value of $K_c$ is 0.136 and is reactant favored.

4 0

3 years ago

Calculate the change in enthalpy for the following reaction, using the bond enthalpy data provided below. (Note: you may round t

aliina [53]

Answer:

-514 kJ/mol

Explanation:

The bond enthalpy which is also known as bond energy can be defined as the amount of energy needed to split one mole of the stated bond. The change in enthalpy of a given reaction can be estimated by subtracting the sum of the bond energies of the reactants from the sum of the bond energies of the products.

For the given chemical reaction, the change in enthalpy of the reaction is:

Δ $H_{rxn} =$ [2(409) + 4(388) + 3(496) - 4(630) - 4(463)] kJ/mol = 818 + 1552 + 1488 - 2520 - 1852 = -514 kJ/mol

3 0

3 years ago

Find if the example is correct or not and explain using CER please. Will give 5/5

ELEN [110]

The Lewis structure the student drew is incorrect. The total number of electrons in bonds and lone pairs is equal to the total number of valence electrons available, then a valid Lewis structure is produced.

The correct structure is the following:

The structure that was drawn by the student was incorrect because the total number of electrons around Oxygen were incorrect, there were 6 instead of 8, which was against the octet rule. The correct structure should have 8 electrons around each atom.

5 0

1 year ago