What is the oxidation number for N in the compound NH3? (Recall that H usually has an oxidation number of +1.)
0 -3
0-1
Ο Ο
O +3

Answer:

You answer is correct

Electrons have a negative charge. The charge on the proton and electron are exactly the same size but opposite. Neutrons have no charge.

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Answer:

D because excited electrons fall back.....

Answer:

cuticle

Explanation:

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Answer:

B(cuticle)

Explanation:

Answer:

3.3g

Explanation:

Given parameters:

Mass of HCl  = 13.5g

Unknown:  

 Mass of water produced  = ?

Solution:

The reaction equation is shown below;

         2HCl   +  CaCO₃  →  CaCl₂  +  CO₂  + H₂O

To solve this problem, let us find the number of moles of the given specie first then we can use that to find the mass of the unknown water.

  Number of moles  = [tex]\frac{mass}{molar mass}[/tex]

           Molar mass of HCl  = 1 + 35.5  = 36.5g/mol

  Number of moles of HCl  = [tex]\frac{13.5}{36.5}[/tex]   = 0.37mol

From the balanced chemical reaction;

      2 mole of HCl will produce 1 mole of H₂O

     0.37mole of HCl will produce [tex]\frac{0.37}{2}[/tex]   = 0.19mole of H₂O

So to find the mass of H₂O;

   Mass  = Number of moles x molar mass

         Molar mass of H₂O  = 2(1) + 16  = 18g/mol

  Mass of H₂O  = 0.19 x 18  =3.3g

Answer:

1. some thing that has matter is an apple, a person,a table. things that does 2.not Light.,Sound.,Heat.Energy.Gravity.Time.A Rainbow.Love.

3. Physical changes only change the appearance of a substance, not its chemical composition. Chemical changes cause a substance to change into an entirely substance with a new chemical formula. Chemical changes are also known as chemical reactions.

4.A chemical reaction is usually accompanied by easily observed physical effects, such as the emission of heat and light, the formation of a precipitate, the evolution of gas, or a color change. Absolute confirmation of a chemical change can only be validated by chemical analysis of the products!

5.Precipitate: In chemistry, a solid formed by a change in a solution, often due to a chemical reaction or change in temperature that decreases solubility of a solid. In meteorology a precipitate is liquid or solid water (rain, snow, etc.) falling from the sky.

6.n simple terms, the endothermic reactions absorb energy from the surrounding that is in the form of heat. On the other hand, an exothermic reaction releases energy into the surrounding of the system.

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Explanation:

Answer:

Chemical

Explanation:

Answer: So if you had 570 cm of ribbon, then 570%2F8.5=67.05 which means that about 67 students can do the experiment (round down to the nearest whole number).

Explanation: If you had 8.5 cm of ribbon, then only 8.5%2F8.5=1 student can do the experiment. If you had 17 cm of ribbon, then 17%2F8.5=2 students can do the experiment.

Answer:

A. Metal mixture is impure

Answer:

Longer wavelengths

Explanation:

The type of wavelength in UV/V spectroscopy is absorbed by easily excited electrons will be longer wavelengths.

The distance a wave-particle travels after completing one oscillation would be its wavelength.

The electric charge of the electron, a subatomic particle, would be a negative elementary charge.

Between around 200 nm (only in near-ultraviolet ) and 800 nm, and absorption spectrometer operates (near infra-red). In that location, only a small fraction of the potential electron jumps can absorb light.

To know more about wavelength

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Answer:

They're both examples of matter changing states.

Explanation:

Clouds = vapor, then forming rain = liquid

water = liquid freezing into ice = solid

Answer:

Earth's gravity is still pulling down on the rocket. When a rocket burns propellants and pushes out exhaust, that creates an upward force called thrust. To launch, the rocket needs enough propellants so that the thrust pushing the rocket up is greater than the force of gravity pulling the rocket down.

Explanation:

Aluminium hydroxide is amphoteric. Because it reacts with both acids and bases. Like any conventional base, the OH radical in Al(OH)3 neutralizes H+ to make water and an aluminium salt. Al(OH)3 solid will also react with excess OH– to dissolve and form the complex ion [Al(OH)4]−.

Answer:

Answer: Aluminium hydroxide ,AI(OH)3,is found in nature as the mineral gribbsite (also know as hydrargillite) and its three much rarer poly morphs

Explanation:

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Answer:

1 Al(NO3)3 + 1 (NH4)3PO4 → 1 AlPO4 + 3 NH4NO3

Explanation:

To balance Al(NO3)3 + (NH4)3PO4 → AlPO4 + NH4NO3 you'll need to be sure to count all of the atoms on each side of the chemical equation.  Once you know how many of each type of atom you can only change the coefficients (the numbers in front of atoms or compounds) to balance the equation.

Important tips for balancing chemical equations:

Answer:

Density = 1.56 g/mL

Explanation:

We have two sort of concentrations in here, so let's combine them.

% by mass means grams of solute in 100 g of solution

M means, moles of solute in 1L of solution.

We know that our solute is KOH (Molar mass = 56.1 g/mol)

We convert the moles of solute to grams:

56.1 g/mol . 13.9 moles = 779.79 g

Now, we know that 50 g of solute are in 100 g of solution

Then, 779.79 g of solute will be contained in (100 . 779.79)/50 = 1559.58 g of solution

Density = mass / volume

1559.58 g of solution / 1000 mL of solution = 1.56 g/mL

Answer:

density is [tex]\frac{mass}{volume}[/tex]

Explanation:

the volume of the block is 4 x 2 x 4.5 and that equals 36. Divide the mass by the volume and you get [tex]\frac{18}{36}[/tex] which is equal to 2 g per cubic centimeters

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Answer:

.

Explanation:

Answer:

0.096 M

General Formulas and Concepts:

Chemistry - Solutions

Explanation:

Step 1: Define

6.25 g Ba(NO₃)₂

250 mL

Step 2: Define conversions

1000 mL = 1 L

Molar Mass of Ba - 137.33 g/mol

Molar Mass of N - 14.01 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of Ba(NO₃)₂ - 137.33 + 2(14.01) + 6(16.00) = 261.35 g/mol

Step 3: Convert

[tex]250 \ mL(\frac{1 \ L}{1000 \ mL} )[/tex] = 0.25 L

[tex]6.25 \ g \ Ba(NO_3)_2(\frac{1 \ mol \ Ba(NO_3)_2}{261.35 \ g \ Ba(NO_3)_2} )[/tex] = 0.023914 mol Ba(NO₃)₂

Step 4: Find Molarity

M = 0.023914 mol Ba(NO₃)₂ / 0.25 L

M = 0.095657

Step 5: Check

We are given 2 sig figs as our smallest. Follow sig fig rules.

0.095657 M ≈ 0.096 M

Answer:

The study of chemistry is about the learning of chemist arts

Answer:

1.11g/cm³

It will sink

Explanation:

Given parameters:

Dimension of the kryptonite:

    W = 3cm

     L  = 6.0cm

     H = 4.0cm

Mass  = 80g

Unknown:

Density of the kryptonite = ?

Solution:

The density of a substance is its mass per unit volume;

 Density  = [tex]\frac{mass}{volume}[/tex]  

 Now let us find the volume;

 Volume  = L x W x H  = 3 x 6 x 4 = 72cm³

So;

    Density  = [tex]\frac{80}{72}[/tex]  = 1.11g/cm³

The substance will not float in water because its density is greater than that of water. It will sink in water.

Answer:

I guess number three (3) Is wrong

Answer: taking thisin advanced middle  school math doubt thats college

Explanation: has to be b or c, asked my teacher honestly everybody on here said b but 1 person said 3 which is partially incorrect but uh

Answer:

[tex]833.72\ \text{torr}[/tex]

Explanation:

[tex]P_g[/tex] = Pressure of gas = [tex]106\ \text{mmHg}[/tex]

[tex]P_a[/tex] = Atmospheric pressure = 0.958 atm

Absolute pressure is given by

[tex]P=P_g+P_a[/tex]

[tex]\Rightarrow P=\dfrac{106}{760}+0.958[/tex]

[tex]\Rightarrow P=1.097\ \text{atm}=1.097\times 760=833.72\ \text{torr}[/tex]

The pressure of the gas in the tank is [tex]833.72\ \text{torr}[/tex]

Answer:

[tex]\Delta G^0_{rxn}=16.81kJ[/tex]

Explanation:

Hello!

In this case, since the Gibbs free energy of any process is related with the enthalpy change, temperature and entropy change as shown below:

[tex]\Delta G^0=\Delta H^0-T\Delta S^0[/tex]

For a chemical reaction it is simply modified to:

[tex]\Delta G^0_{rxn}=\Delta H^0_{rxn}-T\Delta S^0_{rxn}[/tex]

Thus, since the enthalpy of reaction is given as -304.2 kJ and the entropy as -414.2 J/K (-0.4142 kJ/K), at 775 K the Gibbs free energy of reaction turns out:

[tex]\Delta G^0_{rxn}=-304kJ-775K*(-0.4142\frac{kJ}{K} )\\\\\Delta G^0_{rxn}=16.81kJ[/tex]

Whose result means this is a nonspontaneous reaction.

Best regards!

Answer:

C.

Explanation:

Answer:

C

Explanation:

Answer:

Electronegativity increases as you move across the periodic table from left to right.

Explanation:

Answer:

increases

Explanation:

Answer:

b

Explanation:

causes onj the scale of 2 3 4 it equals s

Answer:

Liquids, They are the only one that can change shape to fit the container

Answer:

option A  is correct.

Explanation:

The atoms and molecules in gases are much more spread out than in solids or liquids. They vibrate and move freely at high speeds. A gas will fill any container, but if the container is not sealed, the gas will escape. Gas can be compressed much more easily than a liquid or solid.

Answer:

[tex]\Delta _rH=17.51\frac{kJ}{mol}[/tex]

Explanation:

Hello!

In this case, since the enthalpy change for any process is computed by subtracting the enthalpy of the final state and the enthalpy of the initial state, for the given phase change, we subtract the enthalpy of the liquid (final state) and the enthalpy of the solid (initial state) considering this a melting process:

[tex]\Delta _rH=-390.76\frac{kJ}{mol} -(-408.27\frac{kJ}{mol} )\\\\\Delta _rH=17.51\frac{kJ}{mol}[/tex]

Which makes sense because this process absorbs energy.

Best regards!

The enthalpy change for the sublimation of LiCl(s) → LiCl(l) is 17.51 kJ/mol.

The enthalpy change for the phase change is given by;

ΔH°fproducts - ΔH°freactants.

From the available information in the question;

ΔH°fLiCl(s)   = -408.27 kJ/mol

ΔH°fLiCl(l) = -390.76 kJ/mol

Hence;

ΔH°reaction = (-390.76 kJ/mol) - (-408.27 kJ/mol)

ΔH°reaction = 17.51 kJ/mol

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