Students were given four unknown substances and asked to observe their
characteristics. Their observations are shown in the table below:



Which of the unknown substances is MOST likely a metal?

In the calorimeter, the heat received is the same as the heat released  

Q abs = Q release

Heat can be calculated using the formula:  

Q = mc∆T  

Q = heat, J  

m = mass, g  

c = specific heat, joules / g ° C  

∆T = temperature difference, ° C / K  

Q released by a metallic ore and absorbed by water at calorimeter

Q ore = Q water

m = 0.5 kg = 500 g

c = 4.18 J/g–°C.

Δt = 24.3 - 22 = 2.3

[tex]\tt Q=m.c.\Delta t\\\\Q=500\times 4.18\times 2.3=4807~J[/tex]

Q ore = Q water = 4807 J

m ore = 3.5 kg = 3500 g

Δt = 100 - 24.3 = 75.7

[tex]\tt 4807=3500\times c\times 75.7\\\\c=0.018~J/g^oC[/tex]

Answer:

The mass of 10 moles of helium is: 2.5

Answer:

The number of pioneer species get less as the area has more soil to support complex plants and the competition decreases the role of pioneer species.

Explanation:

Pioneer species like Lichens and Mosses inhabit an area after a major disturbance, such as a volcanic eruption. However, with time the number of pioneer species decreases.

The number of pioneer species get less as the area has more soil to support complex plants and the competition decreases the role of pioneer species.

Answer:

Heat required = 1.23×10⁵J

Explanation:

Given:

Mass (m) = 500 gram

Specific heat = 6,090 J/g

heat of fusion = 247 J/g.

Find:

Heat required

Computation:

Heat required = 247 J/g× 500 g

Heat required = 1.23×10⁵J

Answer:Melting can create steam, kind of like a nukeular plant exept no nukulear rods

Answer:

cytoplasm

Explanation:

cytoplasm carries the nutrients of the cell

Answer:

Which observation provided Albert Einstein the clue that he needed to explain the photoelectric effect? Energy of electrons depends on light's frequency, not intensity. A change in which property of light will have no effect on whether or not the photoelectric effect occurs?

Explanation:

The relative atomic mass of element A : 6.075 u

The elements in nature have several types of isotopes

Isotopes are atoms whose no-atom has the same number of protons while still having a different number of neutrons.

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

Atomic mass is the average atomic mass of all its isotopes

Mass atom X = mass isotope 1 . % + mass isotope 2.% ...

Element A

mass number of isotope 1 = 6 , percent : 92.5%

mass number of isotope 2 = 7, percent : 7.5

Relative atomic mass of element A

[tex]\tt = 92.5\%\times 6+7.5\%\times 7\\\\=5.55+0.525=6.075~u[/tex]

Answer: To calculate the atomic mass add up the mass of protons and neutrons.

I hope I helped!

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:

x = 3 and y= 2

Explanation:

Given equations:

           8x - 3y  = 18  - ---- (I)

           5x + 6y = 27 -------(II)

Solve this problem by elimination;

  In the elimination method, we simply find a common term that can make one of the variables in the two equation the same. Then we either add or subtract to remove the variable.

 Mulitply equation (i) by 5 to give equation III

 Mulitply equation (II) by 8 to give equation IV

     5(8x - 3y) = 5(18) ------- III

     8(5x + 6y) = 8(27) ------- IV

   40x - 15y = 90------- III

   40x + 48y = 216  ------- IV

Subtract  equation III and IV;

        -15y - 48y = 90 - 216

         - 63y = -126

                y = 2

Solve for x;

      40x - 15y = 90;

       40x - 15(2) = 90

         40x - 30 = 90

           40x = 90 + 30

              40x = 120

                 x = 3

Answer:

dont question the world kid

Explanation:

Answer:

air

Explanation:

Answer:

Heat

Explanation:

Heat is a transfer of energy, but it is not made of matter. If you were talking about fire, fire is matter. But the heat from it isn't.

Answer:

"Revolution" refers the object's orbital motion around another object.

plz mark brainliest :DD

Answer:

Explanation:

A 5.430 g mixture of FeO and Fe3O4 is reacted with excess of oxygen to form 5.779 g Fe2O3. Find the masses of FeO and Fe3O4 present in the mixture.

I found the answer by doing the following:

Fe2O3 = 159.69 g/mol

FeO = 71.745 g/mol

Fe3O4 = 231.535 g/mol

5.779 g Fe2O3 / 159.69 g/mol = 0.03619 mol Fe2O3

x + y :rarrow: 0.03619 mol Fe2O3, where x = FeO and y = Fe3O4.

This implies that y = 0.03619 - x.

5.430 g = x*71.745 g/mol + (0.03619 - x)*231.535g/mol

x = 0.01846 mol * 71.745 g/mol = 1.324 g FeO

y = 0.03619 - 0.01846 = 0.01773 mol * 231.535 g/mol = 4.105 g Fe3O4

My question is why doesn't the following work:

4FeO + O2 :rarrow: 2Fe2O3

4Fe3O4 + O2  :rarrow: 6Fe2O3

_______________________

2FeO + 2Fe3O4 + O2 :rarrow: 4Fe2O3

5.779 g Fe2O3 / 159.69 g/mol = 0.03619 mol Fe2O3

Product:reactants in question are in a 2:1 ratio as given by the stoichiometric coefficients.

0.03619 mol / 2 = 0.01810 mol of FeO and 0.01810 mol Fe3O4.

0.01810 mol FeO * 71.745 g/mol = 1.299 g FeO

0.01810 mol Fe3O4 * 231.535 g/mol = 4.191 g Fe3O4

Obviously this doesn't work because the original mixture is 5.430 g and not 1.299 g + 4.191 g = 5.490 g. Why doesn't this work the way I think it should? Thank you.

I tihink it will help you

Answer:

They are equal

Explanation:

took the test

Answer:

ITS A JUST FINISHED

Explanation:

Answer:

1. Is fortnite travis scott burger

2. Beetlejuice the second

3. The measurement is 69420

Explanation:

my mom told me

Two or more than two atoms with different physical or chemical properties can not combine together to form an element. An element  cannot be broken down into simpler substances by a chemical change. The correct option is option A.

Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.

Element is the basic unit of any compound and molecule which can not be broken further. Mixture, solution and compound are composed of two or more than two elements which can be further broken down easily.

Therefore, an element  cannot be broken down into simpler substances by a chemical change. The correct option is option A.

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Answer:

Tea is getting hot on the stove.  

2) As the tea and water gets hot, some combined molecules of tea and water will escape from the teapot.  

3) Those escaped molecules now have the entire free space of the entire room to float around in, which they do (because they have high kinetic energy due to being heated).  

4) Hence, in this scenario, your nose will detect a few of those molecules and you smell hot or warm tea.  

5) Cold tea would be a different story. Cold beverages like cold tea do not have the kinetic energy where molecules can 'break free' of the surrounding container. Someone could be sitting in the room having a can or bottle of cold tea and you would not notice that when you walked in the door.

Answer:

Smallest to Largest:

Clay is smaller then 1/125 mm

Silt is 1/256- 1/16 mm

Sand is 1/16-2 mm

Pebble is 2-64 mm

Cobble is 64-256 mm

Boulder is greater then 256 mm

Explanation:

Answer:

Yes

Explanation:

Lithium can cause nausea, diarrhea, dizziness, change in heart rhythm, muscle weakness, fatigue, and a dazed feeling

Continued use of Lithium could mean fine tremor, frequent urination, and thirst

Source: Webmd.com

Answer: It will sink

Explanation:

To solve this we must be knowing each and every concept related to carbon monoxide. Therefore, carbon monoxide float to the top of the room.

When the carbon in fuels burns inefficiently, a toxic gas known as carbon monoxide is created. It is emitted both naturally—from forest fires or volcanic eruptions, for example—and artificially—through procedures. It is lighter than the air.

By attaching to and removing oxygen from myoglobin, carbon monoxide reduces the oxygen storage capacity in muscle cells, which is another way it upsets the body's processes. If carbon monoxide (CO) leaked into your home, carbon monoxide float to the top of the room. Numerous manufacturing and medicinal items employ carbon monoxide.

Therefore, carbon monoxide float to the top of the room.

To know more about carbon monoxide, here:

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Answer:

The tetanus vaccine is a dose of the bacterium Clostridium Tetani, in inactive form or even a surface molecule that helps the body to actively form the antibody.

The tetanus vaccine has coverage for life, it is mandatory in those countries where the disease became common, such as the USA, Argentina, Chile, Uruguay among others.

Before a surgical act or a suspicion of exposure with this bacterium, the booster of the tetanus vaccine should be administered quickly.

Explanation:

Tetanus disease generates a tetanization of all the muscles of the organism, generating spasmodic contractions, which make it impossible to function and develop life when it affects the diaphragm as it makes breathing impossible.

Tetanization does not affect differently in age or sex, it only consists of contamination with the bacteria to be sufficient.

The sources of contagion are areas of mud or earth, rusty cutting or sharp elements, and poorly hygienic or abandoned areas. In order for the bacteria to be transmitted or the transmission route to be fulfilled, there must be a lesion of loss of continuity of the epithelium or mucosa.