Which ones are elements, compounds I’ll give brainliest.

Answer:

A)16.3% (Hexane's formula is C6H14)

Answer: a) [tex]78.2m^2[/tex]

b) [tex]1.2\times 10m^2[/tex]

c) [tex]2.5m^2[/tex]

d) [tex]81.1m^2[/tex]

Explanation:

Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.

Rules for significant figures:

1. Digits from 1 to 9 are always significant and have infinite number of significant figures.

2. All non-zero numbers are always significant.  

3. All zero’s between integers are always significant.

4. All zero’s preceding the first integers are never significant.

5. All zero’s after the decimal point are always significant.

The rule apply for the multiplication is :

The least number of significant figures in any number of the problem determines the number of significant figures in the answer.

a) [tex]24m\times 3.26m=78.2m^2[/tex]    

b) [tex]120m\times 0.10m=1.2\times 10m^2[/tex]

c) [tex]1.23m\times 2.0m=2.5m^2[/tex]

d) [tex]53.0m\times 1.53m=81.1m^2[/tex]

Answer:

Strong acids contain more A− than weak acids do.

Strong acids contain more H3O+ than weak acids do

Explanation:

When we talk about a strong acid, we are referring to any acid that is completely dissociated or ionized when it is in an aqueous solution.

It is very eager to lose a proton, H+ in solution according Arrhenius definition.

In aqueous solution, a strong acid ionizes as follows:

HA(aq) + H2O → H3O+(aq) + A−(aq)

Since, strong acids ionize completely in solution, strong acids contain a greater H3O+ and A− concentration than solutions of weak acids.

Answer:

A. Strong acids contain more A− than weak acids do.

B. Strong acids contain more H3O+ than weak acids do.

D. Strong acids contain more OH− than weak acids do.

Explanation:

Plato correct

Answer:

Smooth endoplasmic reticulum (SER) is a type of endoplasmic reticulum consisting of tubular vesicles that lack ribosomes on the outer surface and is involved in the synthesis and storage of lipids. Rough ER has ribosomes on the outer surface. Smooth ER does have riboszomes on the outer surface.

Explanation:

Answer:

332g

Explanation:

Given parameters:

Formula units  = 2 x 10²⁴

Unknown:

Mass of the compound = ?

Solution:

The formula of the compound is:

            CaCO₃

      6.02 x 10²³ atoms are contained in 1 mole of a compound

       2 x 10²⁴ atoms will be made up of [tex]\frac{2 x 10^{24} }{6.02 x 10^{23} }[/tex]   = 3.32mole of CaCO₃

 Mass of CaCO₃  = number of moles x molar mass

      Molar mass of CaCO₃  = 40 + 12 + 3(16) = 100g/mol

 Mass of CaCO₃  = 3.32 x 100  = 332g

Answer: thay can't make cells

Explanation:

Answer:

Household cleaners, antiseptics and battery juice are examples of toxic chemicals that you cannot consume because they have high acids concentrations. However some are very healthy such as critic acids found in oranges. :) Hope this helped.

Answer:

Calcination refers to heating a solid to high temperatures in absence of air or oxygen, generally for the purpose of removing impurities or volatile substances.

Explanation:

hope it helps

Answer:

(1) Releases Energy

Explanation:

In the process called cellular respiration, energy is released from oxygen molecules.

Hope this helps!  \ (•◡•) /

Answer:

d = 8.96 g/cm³

Explanation:

Given data:

Volume of sample = 10.0 cm³

Mass of copper = 89.6 g

Density of copper = ?

Solution:

Formula:

d = m/v

d = density

m = mass

v = volume

by putting values,

d = 89.6 g/ 10.0 cm³

d = 8.96 g/cm³

Answer:

Sugar (Sucrose), Corn Syrup (Glucose), Molasses (C6H12NNaO3S)

Explanation:

Each of these is a sweetener.

Answer:

Metals in general have they chemical property of reacting with an acid. Zinc reacts with hydrochloric acid to produce hydrogen gas. This is a chemical property. Chemical change results in one or more substances of entirely different composition from the original substances.

Metal reacts with acid is a chemical property.

Metals react with acids which causes the production of salt and hydrogen gas is released. This is a chemical property because the reactions of reactant produces new type of products which is totally change from the parent material or reactants. The  chemical property is refers to change of one type of matter into another type so we can conclude that reaction of metals with acid is a chemical property.

Learn more: https://brainly.com/question/20677720

The unknown chemical : Nitrogen gas : N₂

Given

1 mole of the unknown chemical

mass = 28 g

Required

The unknown chemical

Solution

A mole is a number of particles(atoms, molecules, ions)  in a substance

This refers to the atomic total of the 12 gr C-12  which is equal to 6.02.10²³, so 1 mole = 6.02.10²³ particles  

Can be formulated :

mol = mass : molecular weight

Molecular weight(MW) = mass : mol

MW=28 g : 1 mol

MW= 28 g/mol

Because this compound is diatomic, it consists of 2 elements of the same type, so this element has a mass number:

28: 2 = 14

The element having the mass number 14 is N

Answer:

NaCl and Br2

Explanation:

Edge 2020

Answer:

The Answer is C: Na and Br3

Explanation:

Answer:

B. Isotopes mean having differing number of neutrons but having the same amount of protons basically.

Explanation:

B. The atoms are isotopes of each other

Given

The first atom : 8 protons, 8 neutrons and 8 electrons

The second atom : 8 protons, 10 neutrons and 10 electrons

Required

Comparison

Solution

A. Atom is said to be neutral if the number of protons and electrons is the same

The first atom neutral

The second atom - anion : charge = -2(10 electron-8 proton)

B. isotopes = the same atomic number and different mass number

The first atom : atomic number = 8, mass number = 16

The second atom neutral : atomic number = 8, mass number = 18

Both : isotopes

C. First atom = neutral, second atom anion (charge = -2)

D. Can exist in nature

Answer:

Unicellular

Explanation:

Unicellular organisms are made up of only a single cell

Answer:

Percent yield = 99.6%

Theoretical yield = 25.5 g

Explanation:

Given data:

Mass of copper = 12.5 g

Mass of copper(II) chloride produced = 25.4 g

Theoretical yield = ?

Percent yield = ?

Solution:

Chemical equation:

Cu + Cl₂       →        CuCl₂

Number of moles of copper:

Number of moles = mass/molar mass

Number of moles = 12.5 g / 63.5 g/mol

Number of moles = 0.19 mol

Now we will compare the moles of copper and copper chloride.

                  Cu          :           CuCl₂

                     1           :               1

                  0.19        :           0.19

Mass of CuCl₂: Theoretical yield

Mass = number of moles × molar mass

Mass = 0.19 mol × 134.45 g/mol

Mass = 25.5 g

Percent yield:

Percent yield = (actual yield / theoretical yield )×100

Percent yield  = ( 25.4 g/ 25.5 g) ×100

Percent yield = 99.6%

Answer:

C. H2(g)

Explanation:

Answer:

Molar mass = 27 g/mol

Explanation:

Given data;

Number of moles of Al = 0.2 mol

Mass of Al = 5.4 g

Molar mass of Al = ?

Solution:

Formula:

Number of moles = mass/molar mass

By putting values,

0.2 mol = 5.4 g/ molar mass

Molar mass = 5.4 g/ 0.2 mol

Molar mass = 27 g/mol

Answer:

B

Explanation:

scientists always look for evidence

Answer:

Yea its B

Explanation: The person above me legit toke the answer out of my mouth

Answer:

How many molecules of water are there in 54 g of H2O H 2 O ? Solution. Molar Mass of H2O H 2 O = 2 + 16 = 18 g/moles. So ,number of moles of H2O H 2 O = Mass/Molar Mass = 54/18 =3 moles. Now 1 moles = 6.022×1023 6.022 × 10 23 molecule.

Answer:

The postulate that all pure samples of a particular chemical compound contain the same elements  combined in the same proportion by mass.

Explanation:

The law of constant composition (or definite proportion) states that all pure samples of a particular chemical compound contain the same elements  combined in the same proportion by mass.

This law implies that irrespective of the source of the sample of the compound or the method by which the sample was prepared, as long as the sample is pure, the elements present in the compound are always combined in a specific ratio by mass. For example, water has the molecular formula H₂O. Irrespective of the water source, for example, tap-water, lake, stream, river or rainfall, each pure sample of water will have the constant composition of 2 atoms of hydrogen to one atom of oxygen.

The given compound exists as XO in nature. Therefore, irrespective of the source or method of preparation, every sample of this compound should have the formula XO. Since the compound prepared by the scientist was XO₂, therefore, the postulate that all pure samples of a particular chemical compound contain the same elements  combined in the same proportion by mass was violated by the scientist. The scientist must have prepared a different compound of the elemental compositions.

Answer:

D. The nucleus occupies very little of the volume but contains most of its mass

Explanation:

Density is an intensive property as it does not depend on the quantity of the substances Whereas mass and volume are extensive property. Therefore,  the nucleus occupies very little of the volume but contains most of its mass. The correct option is option D.

Density tells about the compactness of the substances, how much dense is the substances in other words. Object that is more denser than water they just sink in the water.

Mathematically,

Density = Mass of an atom's nucleus ÷volume marked on the graduated cylinder

Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit.  The nucleus occupies very little of the volume but contains most of its mass.

Therefore,  the nucleus occupies very little of the volume but contains most of its mass. The correct option is option D.

To know more about density, here:

https://brainly.com/question/16894337

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Answer:

The mass of oxygen needed to be pumped in the aquarium is 10 g

Explanation:

Here the value of the degree of solubility of oxygen in water is sought

The solubility of oxygen in fresh water is approximately 1.22 × 10⁻³ mol·dm⁻³ which is equivalent to approximately 40 mg/L

The volume of water the aquarium holds = 250 L

The mass of oxygen required = The solubility of oxygen in water × (The volume of water in the aquarium)

Therefore, the mass of oxygen needed to be pumped in the aquarium = 40 mg/L × 250 L = 10,000 mg

1,000 mg = 1 g

∴ 10,000 mg = 10 g

The mass of oxygen needed to be pumped in the aquarium = 10,000 mg = 10 g.

Answer:

Thermohaline Circulation

Explanation:

The process is known as “Thermohaline Circulation”. In the Earth’s polar regions ocean water gets very cold, forming sea ice. As a consequence the surrounding seawater gets saltier, because when sea ice forms, the salt is left behind. As the seawater gets saltier, its density increases, and it starts to sink.

Answer:

To be stable, an atom or ion should have 8 electrons in the outer shell. This is called the octet rule.

Magnesium is unstable because a magnesium atom has 2 valance electrons in its 3rd shell.

Chlorine is unstable, because a chlorine atom has 7 valance electrons is its 3rd shell.

Chlorine has higher electronegativity than magnesium, so the 2 chlorine atoms will attract 2 electrons from a magnesium atom. This produces a +2 magnesium ion and two -1 chloride ions.

A) A Cl atom donates two electrons to a Mg atom  

B) An Mg atom donates two electrons to a Cl atom.  

C) A Cl atom donates one electron to each of the two Mg atoms.  

D) An Mg atom donates one electron to each of the two Cl atoms. YES

Atoms do not donate any electrons. When a chlorine molecule collides with a magnesium atom, each of the chlorine atoms grab an electron from the outer shell of the magnesium atom. You might think that the magnesium atom would be angry at the chlorine molecule. But, the magnesium atom is much “happier” as a stable +2 ion than a neutral atom. And the chlorine molecule is also “happier” as two -1 chloride ions.

Magnesium chloride is the name for the chemical compounds with the formulas MgCl2 and its various hydrates MgCl2(H2O)x. These salts are typical ionic halides, being highly soluble in water. The hydrated magnesium chloride can be extracted from brine or sea water. Magnesium chloride as the natural mineral bischofite is also extracted (solution mining) out of ancient seabeds; for example, the Zechstein seabed in northwest Europe. Anhydrous magnesium chloride is the principal precursor to magnesium metal, which is produced on a large scale. Hydrated magnesium chloride is the form usually used in prescription oral magnesium supplements.

We are the ones who messed with mother nature. Magnesium chloride was very stable (happy) when it was in the sea water. Humans decided to harvest the MgCl2 and rip it apart to produce little strips of magnesium metal for chemistry class.

In nature, “nobody” freely donates anything to “anyone”. The electrostatic forces in the atoms decide who get the electons.

Sometimes, I just get carried away as I answer peoples’ question.

I hope this helped you.

Answer:

16 g/mol

Explanation:

In CO2, it means we have 1 mole of carbon and 2 moles of oxygen.

However, we want to find the molar mass of just a single mole of oxygen.

Now, from tables of values of elements in electronic configuration, the molar mass of oxygen is usually approximately 16 g/mol.

In essence the molar mass is simply the atomic mass in g/mol

Answer:

90.1km/hr

Explanation:

Given parameters:

Distance  = 30km

Time  = 20s  = 0.33hr

Unknown :

Speed of the car  = ?

Solution:

To solve this problem;

     Speed  = [tex]\frac{distance }{time}[/tex]  

Now insert the parameters and solve;

 Speed  = [tex]\frac{30}{0.333}[/tex]   = 90.1km/hr

Answer:

Density, d = 8.92 g/mL

Explanation:

Let mass of the wooden block, m = 46.83  g

The volume of the object, V = 5.25 mL

We need to find the density of the wooden block. The density of an object is given by its mass per unit volume.

density = mass/volume

[tex]d=\dfrac{46.83\ g}{5.25\ mL}\\\\=8.92\ g/mL[/tex]

So, the density of the wooden block is 8.92 g/mL.

Answer:

0.495 g/cm3

Explanation: