What mass of Ca(OH)2 would you need to make 300.0mL of a 1.2M solution of Ca(OH)2

An isotope of ₂₀⁴⁰X  ⇒₂₀⁴⁴X

The elements in nature have several types of isotopes

Isotopes are atoms that have the same number of protons and a different number of neutrons.

So Isotopes are elements that have the same Atomic Number (Proton)

In the following element notation,

[tex]\large {{{A} \atop {Z}} \right X}[/tex]

X = symbol of elemental atom

A = mass number

  = number of protons + number of neutrons

Z = atomic number

   = number of protons = number of electrons, on neutral elements

For symbol of isotope X :

₂₀X⁴⁰ : atomic number = 20, mass number = 40

A. ₄₀²⁰X : atomic number = 40, mass number = 20, neutrons=20

B. ₂₀⁴⁰X²⁺ : atomic number = 20, mass number = 40, neutrons=20

C. ₂₁⁴⁰X : atomic number = 21, mass number = 40, neutrons=19

D. ₂₀⁴⁴X : atomic number = 20, mass number = 44, neutrons=22

Answer:

I think 7, 4, 6, or 8

I think that one of those is correct

Explanation:

Given that,

The wavelength of microwave radiation = 1 cm = 0.01 m

To find,

The frequency and the energy of a single photon of this radiation.

Solution,

Let f be the frequency of the wave. The relation between frequency and wavelength is given by :

[tex]f=\dfrac{c}{\lambda}\\\\f=\dfrac{3\times 10^8}{0.01}\\\\=3\times 10^{10}\ Hz[/tex]

Let E be the energy of the wave. The energy of the wave is given by :

[tex]E=hf\\\\=6.63\times 10^{-34}\times 3\times 10^{10}\\\\=1.98\times 10^{-23}\ J[/tex]

We know that, [tex]N_A=6.022\times 10^{23}\ \text{photons/mol}[/tex]

Energy :

[tex]E={1.98\times 10^{-23}}\times {6.023\times 10^{23}}\\\\=11.92\ J/mol[/tex]

Hence, this is the required solution.

Answer:

speed is always positive

acceleration may be positive or negative

speed is scalar quantity

accleration vector quantity

Answer:

Percentage yield

Explanation:

The formula given in question above is used to calculate the percentage yield.

The percentage yield of a given reaction is defined as the value obtained in percent by comparing the actual and theoretical yield together. It can be obtained by using the following formula:

Percentage yield = (Actual / Theoretical) × 100

Where:

Learn more about percentage yield: https://brainly.com/question/25910524

Answer:

if the arrangement is symmetrical and the are equal length it is non polar

it the arrows are different lengths and if they do not balance each other or if the arrangement is asymmetrical they are polar

Answer: All living organisms share several key characteristics: sensitivity or response to the environment, reproduction, growth and development, regulation, homeostasis, and energy processing.

Answer:

reactant

Explanation:

oxygen is the one causing the change

Answer:

It is the one that is going into it so i think reactant

Explanation:

Sorry if i am wrong

Answer:

3.06 m

Explanation:

Time of fall be t .

h = ut + 1/2 g t² , h is height , u is initial vertical velocity = 0

h = 1/2 g t²

32 = .5 x 9.8 x t²

t = 2.55 s

During this period , diver will move in horizontal direction also .

Horizontal displacement during fall

=  horizontal velocity x time

= 1.2 x 2.55

= 3.06 m  

Answer:

Mountainous roads are winding and gently sloping in order to reduce the effect of steepness which causes more downward gravitational pull to the vehicles on it. A steeper sloped road would slow the car down to a greater extent that an gently sloping one.

Answer:

wow ok have fun

Explanation:

Answer:

hiiiiiiiii

Explanation:

thank you

Answer:

is number 1

Explanation:

cause i know

The product : Copper oxide

Given

Word equation

Required

The product of the reaction

Solution

The chemical equation can be expressed in terms of:

If we state the word equation  above into a chemical equation(with formula)

CuCO₃ ⇒ CuO + CO₂

This reaction is a type of decomposition reaction

AB⇒A+B

Where the copper carbonate is decomposed into copper oxide and carbon dioxide

As we know, in a chemical reaction, the reactants are on the left and the products are on the right

So that the products of this reaction are copper oxide and carbon dioxide and the reactants are copper carbonate

Answer:

It should be the same as the reactants. Because there is no loss or replacements.

Explanation:

Answer:

The same as the reactants

Explanation:

Answer:

I have two methods to distinguish between concentrated and dilute nitric acid

Method 1: Using magnesium/manganese.

Mg + 2HNO₃ (1%) → Mg(NO₃) + H₂

very very dilute

Mg + 4HNO₃ → Mg(NO₃)+ 2H₂O +2NO₂

concentrated

In the first reaction of magnesium with concentrated nitric acid, hydrogen is evolved.

In the second reaction of magnesium with very very dilute nitric acid, water is evolved.

Using the respective tests for hydrogen and water, we can test them.

Method 2: Using iron.

3 Fe + 8HNO₃→ 3Fe(NO₃)₂ + 4H₂O + 2NO

dilute

Fe + 6HNO₃→ Fe(NO₃)₃ + 3H₂O + 3NO₂

   concentrated

In the first case of method 2,

Fe(NO₃)₂ ⇆ Fe²⁺ + (NO₃) ⁻       Iron with valency 2+ is formed

In the second case of method 2,

Fe(NO₃)₃ ⇄ Fe³⁺ + (NO₃) ⁻        Iron with valency 3+ is formed

Brainlist pls!

As the names suggest, a physical change affects a substance's physical properties, and a chemical change affects its chemical properties. Many physical changes are reversible (such as heating and cooling), whereas chemical changes are often irreversible or only reversible with an additional chemical change.

(hope this helps ^^)

Answer:

Explanation:

The ion and the neutral atom both contain 20 protons. Generally the protons stay in the nucleus forever.

Answer:

9.5625 gram

Explanation:

Molarity = mass in gram ÷ molar mass × volume in dm3

Mass in gram = molarity× molar mass × volume of solution in dm3

Mass in gram = 0.450×42.5×0.5=9.5625 g

Answer:

If the rock can't scratch a knife, but glass, it's a 7-10 (Hard Rock)

It's between Quartz and Topaz.

So the answer is,

Answer:

Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, pollen and mold spores may be suspended as particles. Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's also called smog. Air pollution is the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are different types of air pollutants, such as gases, particulates, and biological molecules. Air pollution is caused by solid and liquid particles and certain gases that are suspended in the air. These particles and gases can come from car and truck exhaust, factories, dust, pollen, mold spores, volcanoes and wildfires. Air pollution can also cause headaches, dizziness, and nausea. ... Long-term health effects from air pollution include heart disease, lung cancer, and respiratory diseases such as emphysema. Air pollution can also cause long-term damage to people's nerves, brain, kidneys, liver, and other organs. The most basic solution for air pollution is to move away from fossil fuels, replacing them with alternative energies like solar, wind and geothermal. Producing clean energy is crucial. But equally important is to reduce our consumption of energy by adopting responsible habits and using more efficient devices.

Its sad of what our world has become

8 sentence paragraph:

Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, pollen, and mold spores may be suspended as particles. Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's also called smog. Some air pollutants are poisonous. Inhaling them can increase the chance you'll have health problems. People with heart or lung disease, older adults, and children are at greater risk from air pollution. Air pollution isn't just outside like the air inside buildings can also be polluted and affect your health.

Answer:

ta da

Explanation:

If you need help, ask a parent or teacher. Or yes, one of us can help! Just let us know what you're having trouble with, and we can see how we can help.

Answer:

c

Explanation: i am for sure

Answer:

See the answer below

Explanation:

The percentage by mass of a substance in a mixture is the ratio of the mass of the substance and the mass of the entire mixture.

Hence, when concentrated HNO3 is said to be 69% by mass of nitric acid, it means that the solution of the acid has 69% HNO3 and 31% water in terms of mass. More specifically, 100 g of the solution of the acid would contain 69 g of HNO3 and 31 g of water respectively,

Answer:

It's used as a seasoning for the taste of food. It also helps to bring out the natural flavours in the food.

Answer:

5

Explanation:

Answer:

2 in the first and 4 in the second

Explanation:

in an atom the first energy level has only 2 spaces for electrons, as the number electrons goes up so does the amount of energy levels