The Moon rises at noon and sets at midnight. What is the phase of the Moon?

A substance is found to consist of 1.900g of silver, 0.250g of nitrogen, and 0.850g of oxygen. what is the percent by mass of ox

Galina-37 [17]

The percentage by mass of oxygen in the compound

find the total mass=( 1.900+ 0250 +0.850) = 3
the percentage mass mass of oxgyen/total mass x100

that is (0.850/3) x100=28.33%

7 0

3 years ago

How many kJ of heat are released by the reaction of 25.0 g of Na2O2(s) in the following reaction? (M = 78.0 g/mol for Na2O2)

solong [7]

-20.16 KJ of heat are released by the reaction of 25.0 g of Na2O2.

Explanation:

Given:

mass of Na2O2 = 25 grams

atomic mass of Na2O2 = 78 gram/mole

number of mole = $\frac{mass}{atomic mass of 1 mole}$

= $\frac{25}{78}$

=0. 32 moles

The balanced equation for the reaction:

2 Na2O2(s) + 2 H2O(l) → 4 NaOH(aq) + O2(g) ∆Hο = −126 kJ

It can be seen that 126 KJ of energy is released when 2 moles of Na2O2 undergoes reaction.

similarly 0.3 moles of Na2O2 on reaction would give:

$\frac{126}{2}$ = $\frac{x}{0.32}$

x = $\frac{126 x 0.32}{2}$

= -20.16 KJ

Thus, - 20.16 KJ of energy will be released.

6 0

3 years ago

Match these items. 1. moles per liter of solution solute 2. spreading out Keq 3. substance being dissolved diffusion 4. general

Degger [83]

Answer:

1. moles per liter of solution - Molarity

2. spreading out - diffusion

3. substance being dissolved- solute

4. general equilibrium constant - Keq

5. the substance doing the dissolving in a solution - solvent

6. solubility product constant - Ksp

Explanation:

Number of moles of substance being dissolved in one liter of solution is defined as molarity

Solute is the substance which is dissolved and solvent is the substance into which the solute is dissolved. For example salt is solute and water is solvent.

Ksp defines the solubility product constant which indicates the equilibrium between a solid and solution and the number of ions of solid required to achieve this equilibrium.

Keq depicts the scenario where reactant and product concentrations are constant in a chemical reaction.

Hence, the correct match is

1. moles per liter of solution - Molarity

2. spreading out - diffusion

3. substance being dissolved- solute

4. general equilibrium constant - Keq

5. the substance doing the dissolving in a solution - solvent

6. solubility product constant - Ksp

8 0

3 years ago

Watch the animation and identify the correct conditions for forming a hydrogen bond. check all that apply. check all that apply.

OLga [1]

The ch4 molecule exhibits hydrogen bonding.
This statement is false. A CH4 molecule do not have a hydrogen bonding instead it has dipole dipole attraction.

Hydrogen bonding occurs when a hydrogen atom is covalently bonded to an N, O, or F atom.
This would be a true statement. A hydrogen bond is present when an atom of hydrogen shares electrons with O, N or F atom.

A hydrogen bond is equivalent to a covalent bond.
This is a false statement. A hydrogen bond is an intermolecular force of attraction while covalent bond is a intramolecular force. So, they would mean different things.

a hydrogen bond is possible with only certain hydrogen-containing compounds.
This would be true. Without the presence of an hydrogen atom definitely there would be no hydrogen bond.

a hydrogen atom acquires a partial positive charge when it is covalently bonded to an f atom.
This would be true since a HF is a polar molecule.

6 0

3 years ago

Read 2 more answers

A mixture of 0.10 mol of NO, 0.050 mol of H2, and 0.10 mol of H2O is placed in a 1.0- L vessel at 300 K . The following equilibr

umka2103 [35]

Answer:

The concentration of N2 at the equilibrium will be 0.019 M

Explanation:

Step 1: Data given

Number of moles of NO = 0.10 mol

Number of moles of H2 = 0.050 mol

Number of moles of H2O = 0.10 mol

Volume = 1.0 L

Temperature = 300K

At equilibrium [NO]=0.062M

Step 2: The balanced equation

2NO(g) + 2H2(g) → N2(g) + 2H2O(g)

Step 3: Calculate the initial concentration

Concentration = Moles / volume

[NO] = 0.10 mol / 1L = 0.10 M

[H2] = 0.050 mol / 1L = 0.050 M

[H2O] = 0.10 mol / 1L = 0.10 M

[N2] = 0 M

Step 4: Calculate the concentration at the equilibrium

[NO] at the equilibrium is 0.062 M

This means there reacted 0.038 mol (0.038M) of NO

For 2 moles NO we need 2 moles of H2 to produce 1 mol N2 and 2 moles of H2O

This means there will also react 0.038 mol of H2

The concentration at the equilibrium is 0.050 - 0.038 = 0.012 M

There will be porduced 0.038 moles of H2O, this means the final concentration pf H2O at the equilibrium is 0.100 + 0.038 = 0.138 M

There will be produced 0.038/2 = 0.019 moles of N2

The concentration of N2 at the equilibrium will be 0.019 M

5 0

3 years ago