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Explanation : số mol glucose 3.8M là :

n = Cm . V = 3.8 . 25 =95

=> Cm khi pha loãng = [tex]\frac{n}{V}[/tex] = [tex]\frac{95}{250}[/tex] = 0.38M

According to molar concentration, the  concentration of a solution formed by diluting 25.0 ml of a 3.8 M glucose solution to 250 ml is 0.38 M.

Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.

The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.

In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.In case of 2 solutions given it is calculated as M₁V₁=M₂V₂,on substitution, M₂=3.8×25/250=0.38 M.

Thus,  the  concentration of a solution formed by diluting 25.0 ml of a 3.8 M glucose solution to 250 ml is 0.38 M.

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Explanation:

here's the answer to your question

Answer:

The volume of the base is 0.05819·x L, where x is the number of moles of base that combines with one mole of sulfuric acid

Explanation:

The volume of the sulfuric acid, V = 25.3 mL = 25.3 × 10⁻³ L

The concentration of the sulfuric acid, c = 2.30 M

The concentration of the base, [tex]c_{base}[/tex] = 1.00 M

Let the mole ratio of the acid to base be 1 : x

The number of moles of sulfuric acid present, n = c × V

∴ n = 2.30 M/L × 25.3 × 10⁻³ L = 0.05819 moles

The number of moles of sulfuric acid present, n = 0.05819 moles

1 mole of sulfuric acid combines with x moles of base

Therefore, 0.05819 moles of sulfuric acid will combine with 0.05819·x moles of base

The number of moles of base, [tex]n_{base}[/tex] = 0.05819·x moles

Therefore, the volume of base, [tex]V_{base}[/tex] = [tex]n_{base}[/tex]/[tex]c_{base}[/tex]

∴  [tex]V_{base}[/tex] = 0.05819·x/1 ≈ 0.05819·x L

The volume of base,  [tex]V_{base}[/tex] ≈ 0.05819·x L.

Answer:

absolutely B because Al2O3 could react with axit and bazo

Explanation:

Answer:

"Aluminum oxide, beryllium oxide, tin oxide, zinc oxide all are amphoteric. They have reactions as both a base and an acid."

Explanation:

Answer:

The molar mass of gas Q is 43.923 g/mol

Explanation:

The given volume of ethane gas that diffuses through a porous plug in 100 seconds = 100 cm³

Therefore;

The rate of diffusion of ethane gas through the porous plug, [tex]v_{ethane}[/tex], is given as follows;

[tex]v_{ethane}[/tex] = (100 cm³/100 s) = 1 cm³/s

The molar mass of ethane, C₂H₆ = 2×12 g/mol + 6×1 g/mol = 30 g/mol

The given volume of gas, Q, that diffuses through a porous plug in 121 seconds = 100 cm³

∴ The rate of diffusion of the gas, Q, [tex]v_Q[/tex] = 100/121 cm³/s

Graham's Law of diffusion states that the rate of diffusion of a gas is inversely proportional to the square root of the molecular mass of the gas

Mathematically, we have;

[tex]\dfrac{v_A}{v_B} =\sqrt{\dfrac{m_B}{m_A} }[/tex]

Where;

[tex]v_A[/tex] = The rate of diffusion of gas A

[tex]v_B[/tex] = The rate of diffusion of gas B

[tex]m_A[/tex] = The molar mass of the gas A

[tex]m_B[/tex] = The molar mass of the gas B

Therefore, for ethane and gas Q, measured under the same condition, we have;

[tex]\dfrac{v_{ethane}}{v_Q} =\sqrt{\dfrac{m_Q}{m_{ethane}} }[/tex]

[tex]\dfrac{1 \ cm^3/s}{\dfrac{100}{121} \ cm^3/s} =\sqrt{\dfrac{m_Q}{30 \ g/mol} }[/tex]

[tex]m_Q = \left ({\dfrac{121}{100} } \right) ^2 \times 30 \ g/mol = 43.923 \ g/mol[/tex]

The molar mass of gas Q, [tex]m_Q[/tex] = 43.923 g/mol.

Answe:

Explanation:

số mol của H2S là : 68/22.4=3.03 nha

Answer:

The motion towards or away from us based on the Doppler effect and corresponding red shift or blue shift.

Explanation:

The emission and absorption spectra demonstrates the lines where light has been absorbed by the atoms. The spikes can be observed due to atoms releasing photons at those wavelengths. Infrared and ultra violet waves can be observed during spectroscopy.

Answer:

Explanation:

6.         p⁺      e⁻

Ca²⁺    20     18

F⁻          9      10

O²⁻        8      10

Na⁺       11      10

7. Physical properties of matter are properties that can be measured or observed without matter changing to an entirely different substance. These include odor, boiling point, melting point, density, electrical conductivity and heat conductivity.

Separation of mixture:

Chromatography involves solvent separation on a solid medium.

Distillation takes advantage of differences in boiling points.

Evaporation removes a liquid from a solution to leave a solid material.

Filtration separates solids of different sizes.

Funnel partitioning with solvents. Solvent dissolves one component but not the other.

8.Bulk Elements => Carbon, Hydrogen, Oxygen, Nitrogen, Sulfur & Phosphouous

Microminerals are those minerals needed in less than 100 mg quantities. Trace minerals or trace elements are usually needed in microgram quantities. Microminerals include iron, zinc, copper, iodine, fluoride, chromium, cobalt, selenium, manganese, and molybdenum.

Diatomic Molecules => H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂

9. Electron Configurations

    Na: 1s²2s²2p⁶3s¹ => valence = 3s¹

    N:   1s²2s²2p³ => valence = 2s²2p³

    Al:  1s²2s²2p⁶3s²3p¹ => valence = 3s²3p¹

Valence is the highest principle quantum number (or, principle energy level  ~ ring) in the electron configurations.

10.moles of glucose = 450g/180.16 g/mol =2.50 moles

   C₂H₆O₂ = 2(12) + 6(1) + 2(16) = 24 + 6 + 32 = 62 g/mole

Answer:

D. Shaking a cake [...]

Explanation:

None of the rest are actual physical models representing earthquakes.

Hope that's right! :D

Answer:

hexane

Explanation:

This is a 6- carbon hydrocarbon with no multiple bonds or any functional groups (such as -OH). Thus, the prefix 'hex' refers to the 6 carbons and 'ane' refers to the molecule being an alkane.

Naming molecules:

Number of carbons

• pentane: 5 carbons

• hexane: 6 carbons

• heptane: 7 carbons

• octane: 8 carbons

• nonane: 9 carbons

Functional groups (for 6- carbons molecules)

• Alkene (C=C): hexene

• Alcohol (-OH): hexanol

• Alkyne (C≡C): hexyne

2HCl + Mg => MgCl2 + H2

Answer:

hydrogen is abundant in nature

Answer:

B

Explanation:

because Mg is stronger than Al

Answer:

The correct answer is - Economic concerns may prevent it from solving problems.

Explanation:

Scientific research is influenced by various factors. Science helps in the solving of human problems. However, scientific research can need to be supported by many factors such as Huge amounts of money that need to be invested in performing out particular scientific research to solve problems.

For science, there are requirements of Laboratories and lab supplies such as the equipment and experts need to train the personnel on how to use it.

Thus, economic factors play a huge role in scientific research.

Answer:

As the ballon rises higher the atmospheric pressure will drop if the ballon is made of an elastic material,it will stretch to allow the gas inside it to expand

Explanation:

"Its bonds are formed by large differences in electronegativity" is the statement among the choices given in the question that is generally true about CaCl2.

Answer:

Xenon

Explanation:

The core electrons of an element are the electrons that do not take part in the chemical reactions of the element

The electronic configuration of barium Ba is presented as follows;

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s²

2+2+6+2+6+2+10+6+2+10+6

The valence electrons of boron are the 6s² electrons

The core electrons of boron are the; 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶

The electronic configuration of xenon, Xe, which is the previous noble element before barium, is presented as follows;

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ which is the same as the core electrons of barium

Therefore, the total number of electrons in xenon is equal to the number of core electrons in barium

Answer:

Ammonium chloride, iron ,Sulphur and salt mixed together... they can be separated in the following methods.

1. Ammonium chloride is separated by sublimination... NC4CI is sublimable. Heat the mixture in a china dish and collect the funds of NC4CI (sublimable substance)

2. Bring a magnet close to the remaining mixture. Iron is magnetic substance and thus, it will be attracted towards the magnet. Iron is separated.

3. Sulphur is insoluble in water and salt is soluble. Add water to the remaining mixture and then wait for sedimentation. Separate the sulphur by decantation.

4. Heat the filtered salt solution to obtain salt.

Answer:

here's the answer to your question

Explanation:

an acid will give away a proton and become a conjugate base.

A base will accept a proton and become a conjugate acid.

Answer:

For example, the bond between the sodium and chlorine atoms in sodium chloride (NaCl) is formed by the transfer of an electron from sodium to chlorine, creating Na + and Cl – ions. ... The electrostatic attraction between these ions provides the bonding in NaCl.

Explanation:

253°C + 273.15 = 526.15K

526.15 kelvins

Answer:

Explanation:

As per being a Group 7 element, it would gain one electron, which changes it's charge to 1-. It is therefore negatively charged, having a full outer shell of 8, having its electronic structure to be at 2,8,8.

Burning a sugar cube is a chemical change. Fire activates a chemical reaction between sugar and oxygen. The oxygen in the air reacts with the sugar and the chemical bonds are broken. Burning sugar leads to reaction of sugar with oxygen in air and leads to formation of carbon dioxide and water. The change is irreversible and is thus a chemical change

Answer:

0.7602 g/L

Explanation:

We'll begin by calculating the molar mass of NH₃. This can be obtained as follow:

Molar mass of NH₃ = 14.01 + (3×1.01)

= 14.01 + 3.03

= 17.04 g/mol

Finally, we shall determine the density of ammonia, NH₃. This can be obtained as follow:

Temperature (T) = 273 K

Pressure (P) = 1 atm

Molar mass of NH₃ (M) = 17.04 g/mol

Gas constant (R) = 0.0821 atm.L/Kmol

Density (D) =?

D = PM / RT

D = (1 × 17.04) / (0.0821 × 273)

D = 17.04 / 22.4133

D = 0.7602 g/L

Answer:

It is A

Explanation:

Answer:

they have weak intermolecular forces

Explanation:

Desposition of solid matter in a solution

C.

This is basically the definition of percent composition which is how much mass a element contributes to a specific molecule.

Answer: B.

Explanation:

the relative amount of mass an atom contributes to a molecule

Answer:

don't know..............