I don't understand this :c
help me please​

Answer:

[tex]E=4.5\times 10^{-18}\ J[/tex]

Explanation:

It is given that, the frequency of Ultraviolet radiation is [tex]6.8\times 10^{15}\ Hz[/tex]

We need to find the energy of the photon. The formula for the energy of a photon is given by :

[tex]E=hf\\\\\text{Where h is Planck's constant}\\\\E=6.63\times 10^{-34}\times 6.8\times 10^{15}\\\\E=4.5\times 10^{-18}\ J[/tex]

So, the energy of the photon is [tex]4.5\times 10^{-18}\ J[/tex].

I tihink it will help you

Answer:

peer reviewing

Explanation:

Its peer reviewing because there peers and there reviewing eachothers work

The process whereby scientists check each other’s work is peer reviewing.

Peer group are the groups of people of same age, same background with same interest.

In the peer reviewing process group of members will check, evaluate and correct each others work, which in turn help the members of the group to update their work.

Hence, option (c) is correct i.e. peer reviewing is the process whereby scientists check each other’s work.

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To find the number of atoms, we multiple the number of mols by Avogadro's number, about 6.02x10^23

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Answer:

to calculate the numbers of atoms in a sample, divide it's weight in grams by the amu atomic mass from the periodic table, then multiply the result by avogadro's number: 6.0 × 10^24

Answer:

Sugar will dissolve, so water.

Explanation:

Sugar is a bicubacle food source you could say, sand will not evaporate or dissolve in the water since it is not a 3c2e source. Using water will seperate them.

Answer: Heat

Explanation:

Because is you put water and sand in a container you can separated by boiling the water and all the water would evaporate and the sand would stay.

Answer:

Absorption

Explanation:

I think from Quizlet

Answer:

1,) True

2.) False

3.) A Moraine

Explanation:

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Answer:

Chemical changes cause a substance to change into an entire substance with a new chemical formula. Chemical changes are also known as chemical reactions. The “ingredients” of a reaction are called reactants, and the results are called products.

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Answer:

Lithium is a naturally occurring alkali metal, which living organisms ingest from dietary sources and which is also present in trace amounts in the human body. In much higher concentrations, lithium is effective as a medication for mania and mood swings including manic depressive disorders

Answer:

1   Ca(OH)2 + 1  (NH4)2SO4   ---> 1 CaSO4 + 2 NH3 + 2 H2O

Explanation:

The photo I attached should make more sense as an explanation.

When balancing equations, the first and most important step is to count the # of each type of element on each side.

In this problem there are 5: Ca, O, H, N, and S.

Once you do that you can begin balancing.

Here is the initial tally for the elements in this problem:

On the left.....

Ca - 1

N - 2

S - 1

O - 6

H - 10

On the right.....

Ca - 1

N - 1

S - 1

O - 5

H - 5

Looking at these values, we can see N, O, and H all need adjusting the right side. You should never start balancing with O or H unless they are the only elements that need adjusting. They usually balance out with the rest of your work or with water in the end.

So given all of that, you should start balancing with N on the right. Giving NH3 a coefficient of 2 will change the number of Nitrogen atoms on the right to 2. Be careful though! It will also change the number of Hydrogen atoms from 5 to 8 (because (2*3) =6 and 6+2 =8).

Let's tally our numbers again.

On the left..... (these should be unchanged)

Ca - 1

N - 2

S - 1

O - 6

H - 10

On the right.....

Ca - 1

N - 2

S - 1

O - 5

H - 8

Okay, now we see only O and H need adjusting on the right. Luckily there is H2O so we can do that without impacting the number of other atoms.

Give H2O a coefficient of 2 and count the number of atoms on the right again.

On the right.....

Ca - 1

N - 2

S - 1

O - 6 (because 4 from CaSO4 plus 2 from 2H2O = 6)

H - 10 (6 from NH3 plus 4 from 2H2O = 10)

Do these numbers match what you have on the the left side of the equation? Yes! It is balanced so you do not need to adjust anymore. Your coefficients in the answer will be 1-1-1-2-2.

Answer:

See explanation

Explanation:

An intrinsic property is a property that is internal, that is, it characterizes the substance under study. The possession of an intrinsic property depends on the nature of the substance. An intrinsic property does not depend on amount of substance but on the nature of the substance.

Examples of intrinsic properties include; Density. Solubility, Melting Point, Freezing Point, Boiling Point, Conductivity etc.

Intrinsic properties really represent the matter that is being studied. For instance, the boiling point of water will always be 100°c. No other liquid can boil exactly at that temperature. Hence, this intrinsic property can always be used to identify an unknown liquid as water.

The students were right, studying intrinsic properties accurately represent the matter that is being studied.

Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

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

From the question

mass = 5.05 g

density = 3.25 g/mL

We have

[tex]volume = \frac{5.05}{3.25} \\ = 1.5538461...[/tex]

We have the final answer as

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Answer:

B. How many of each atom are present in the compound

D. the simplified ratio of atoms in relation to each other

Explanation:

In a chemical formula, chemical elements or atoms are represented by a chemical symbol for example Fe for iron and Na for sodium, and the number of each atom is represented by a subscript such as CO2, where 2 is a subscript representing 2 atoms of oxygen.

A subscript represents the number of each atom in the compound and the simplified ratio of atoms in relation to each other. The simplified ratio of atoms in relation to each other means subscript shows the contribution of both the atoms in the compound, for example: N2 + 3H2 => 2NH3, it means the subscript showing the ratio or proportionate of atoms that is 2:2 for both nitrogen and hydrogen.

The subscript is always written below and to the right of the chemical symbol.

Hence, the correct answer is "B. How many of each atom are present in the compound and D. the simplified ratio of atoms in relation to each other"

Answer:

Common uses of oxygen include production of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, oxygen therapy, and life support systems in aircraft, submarines, spaceflight and diving.

Answer:

Explanation:

The density of a substance can be found by using the formula

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

From the question we have

[tex]density = \frac{0.256}{100} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

After 7.648 days, you will see one quarter.

Explanation:

1 → 0.5 → 0.25

Since half life of radon-222 is 3.824 days, you need twice this time to get one quarter at the end.

2 ⋅ 3.824 = 7.648 days.

Answer: Acoustic Foam.

Explanation:

Acoustic Foam: This is a kind of material, which is commonly known as it called a Studio Foam, it has a kind of wedge or pyramid shape that plays a big role in absorbing sound. Brian would have to use acoustic foam by placing them round the walls and ceiling as this would stop any echoing sound and in return give a crisp and clear sound when music is been played it the studio.

Answer:bet

Explanation:

Answer: 45

Explanation: it would be 45 bc if the value is 5 and over the number goes up and if it is lower than 5 it would stay the same.

Answer:

45 is the answer

Explanation:

Answer: Christy won Molly by 12cm

Explanation:

Ist step

Molly's ;ong jump was 118.3cm

Christy long jump was 51.18inches

2nd Step

we change christy score to cm so we can compare

1 inch = 2.54cm.

therefore 51.18 inches = 51.18 x 2.54= 129.9972cm

Christy won molly by 129.9971cm-118.3cm=11.69 rounded to 12cm

Christy won Molly by 12cm

Answer:

a) 0.000765kg

b) 1340mg

c) 0.0342g

Explanation:

a) 1000g = 1kg

0.765g= 0.765/ 1000

= 0.000765g

b) 1g = 1000mg

1.34g = 1.34 × 1000

= 1340mg

c) 1000mg = 1g

34.2mg = 34.2/1000

= 0.0342g

Answer:

A) one electron in each orbital

Explanation:

Orbitals get electrons one at a time. If there are three electrons and three empty orbitals, then one electron will go into one orbital!

Answer:

The rule states that for a given electron configuration, the lowest energy term is the one with the greatest value of spin multiplicity. This implies that if two or more orbitals of equal energy are available, electrons will occupy them singly before filling them in pair

Explanation:

Answer:

Al2 O3 or 2:3

Explanation:

The aluminum oxide consists of two elements, which are oxygen atoms and aluminum atoms, and there are 2 aluminum atoms and 3 oxygen atoms in aluminum oxide. The ratio from aluminum atoms to oxygen atoms is 2:3.

There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, the ratio of aluminum atoms to oxygen atoms in aluminum oxide is  2:3.

Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.

An ionic compound is a metal and nonmetal combined compound.  Ionic compound are very hard. They have high melting and boiling point because of strong ion bond. The ratio of aluminum atoms to oxygen atoms in aluminum oxide is  2:3. Aluminium oxide is an ionic compound.

Therefore, the ratio of aluminum atoms to oxygen atoms in aluminum oxide is  2:3.

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Answer:

a particle

Explanation:

matter takes up space, and particles take place in atoms

Answer:

plasma is a state of matter

Ores: metal/coal (iron, gold, coal)

Mineral: not metal, (Granite, limestone,

Answer:

A. a wild dog that finds and mates with a domestic dog.

Explanation:

Answer:

Molar mass of gas = 160 g/mol

Explanation:

Given data:

Mass of sample gas = 1.28 g

Temperature of sample gas = 127°C (127+273 = 400K)

Pressure of sample gas = 1 atm

Volume of sample gas = 0.250 L

Molar mass of gas = ?

Solution:

Formula:

PV = nRT

R = general gas constant = 0.0821 atm.L/ mol.K

Now we will put the values in formula.

1 atm × 0.250 L = n × 0.0821 atm.L/ mol.K ×400K

0.250 L.atm   = n ×32.84atm.L/ mol

n = 0.250 L.atm/32.84atm.L/ mol

n = 0.008 mol

Molar mass of gas:

Number of moles = Mass/molar mass

0.008 mol = 1.28 g / molar mass

Molar mass = 1.28 g / 0.008 mol

Molar mass = 160 g/mol