!!!!!!URGENT!!!!!!
What do the coefficients in the following balanced chemical equation mean?
2H2 + O2 + 2H2O

A) 2 moles of hydrogen and 1 mole of oxygen in the reactants

B) 2 moles of oxygen and 1 mole of hydrogen in the reactants

C) 2 moles of oxygen and 1 mole of hydrogen in the products

D) 2 moles of hydrogen and 1 mole of oxygen in the products

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:

–2400 N

Explanation:

This is a physics question. However, the answer to the question is given below.

We'll begin by converting 36 Km/hr to m/s. This can be obtained as follow:

3.6 Km/hr = 1 m/s

Therefore,

36 Km/hr = 36 Km/hr × 1 m/s / 3.6 km/hr

36 Km/hr = 10 m/s

Thus, 36 Km/hr is equivalent 10 m/s.

Next, we shall determine the acceleration of the car. This can be obtained as follow:

Initial velocity (u) = 10 m/s

Final velocity (v) = 0 m/s

Time (t) = 5 s

Acceleration (a) =?

a = (v – u) / t

a = (0 – 10) / 5

a = – 10 / 5

a = –2 m/s²

Finally, we shall determine the force required to stop the car. This can be obtained as follow:

Mass (m) = 1200 Kg

Acceleration (a) = –2 m/s²

Force (F) =?

F = ma

F = 1200 × –2

F = –2400 N

NOTE: The negative sign indicate that the force is in opposite direction to the motion of the car.

1 meter = 1000 km

2500 meter = 2500/1000 km

= 2.5 km

Answer: A reaction element are those elements that can take part in a chemical reaction.

Explanation:

An element is made up of atoms that has the same atomic number. It is the basic material of which all matter is composed of. These elements cannot be broken down further into smaller substances by any chemical reaction. Each element has a unique number of protons in its atom. For example,

--> a hydrogen atom has 1 proton,

--> a Helium atom has 2 protons,

--> a Lithium atom has 3 protons, and

--> a carbon atom has 6 protons.

A chemical reaction on the other hand involves rearrangement of the constituent atoms of reactants to create different substances as products. The bonds between atoms are either broken or created to form new molecules. There are different types of chemical reaction which includes:

--> Decomposition reaction

--> Neutralization reaction

--> single displacement reaction and

--> combustion reaction.

Answer:

liquid form

Explanation:

am i right? if right like

Answer:

semi-liquid at room temperature

Explanation:

freezing point depression is a phenomenon that describes why adding a solute or solvent results in the lowering of the freezing point of the solvent

Answer:

16 g

Explanation:

Step 1: Write the balanced equation

2 Na + Cl₂ ⇒ 2 NaCl

Step 2: Identify the limiting reactant

The theoretical mass ratio (TMR) of Na to Cl₂ is 46:71 = 0.65:1.

The experimental mass ratio (EMR) of Na to Cl₂ is 10:10 = 1:1.

Since EMR > TMR, Cl₂ is the limiting reactant

Step 3: Calculate the mass of NaCl produced

The theoretical mass ratio of Cl₂ to NaCl is 71:117.

10 g Cl₂ × 117 g NaCl/71 g Cl₂ = 16 g NaCl

Answer:

B. Protons and Neutrons

Answer:

Option"B" is correct.

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Answer:

In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed.

Answer:

7.2

Explanation:

you first have to find the number of moles of nitrogen dioxide by using the number of moles for calcium nitrate and the mole to mole ratios

number of moles of calcium nitrate=mass/mm

=16.4/102

=0.16g/mol

then you use the mole to mole ratios

2 : 4

0.16: x

2x/2=0.64/2

x=0.32g/moles of nitrogen dioxide

then you use the formula for the volume

v=22.4n

=22.4×0.32

=7.2

I hope this helps

Answer:

i is the correct answer.

Explanation:

the RAM of aluminum is indeed 27. And since the RAM of substances are measured in terms of the C-12 isotope then R indeed explains why the RAM Al is 27.

Answer:

Metals on the left of the Periodic Table.

Non-Metals on the top-right, plus Hydrogen.

The correct option for the process used to refine aluminum from its bauxite ore is option D.

D. Smelting

The reason why smelting is the correct choice is as follows;

Bauxite is the aluminum ore from which alumina, also known as aluminum

oxide, Al₂O₃, is produced. Bauxite is extracted from the topsoil regions of

some subtropical and tropical regions, and the Bayer process is primarily

then used to produce alumina from the bauxite.

Aluminum is produced from the alumina by an aluminum smelting process

known as the Hall—Heroult electrolytic process which involves the use of a

carbon anode and direct current to produce aluminum by reducing the

aluminum oxide

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Answer:

"Endothermic reaction: In an endothermic reaction, the products are higher in energy than the reactants. Therefore, the change in enthalpy is positive, and heat is absorbed from the surroundings of the reaction."

Explanation:

When enthalpy is positive and delta H is greater than zero, this means that a system absorbed heat. This is called an endothermic reaction. When enthalpy is negative and delta H is less than zero, this means that a system released heat. This is called an exothermic reaction.

The sign of q for an endothermic process is positive because the system is gaining heat. A chemical reaction or physical change is exothermic if heat is released by the system into the surroundings. Because the surroundings are gaining heat from the system, the temperature of the surroundings increases.

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The steps involved in the manufacture of sulphuric acid by contact process:

(1) Sulphur (or iron pyrites) are burnt in air to form sulphur dioxide.

  S+O2→SO24FeS2+11O2→2Fe2O3+8SO2

(2) Catalytic oxidation of sulphur dioxide to sulphur trioxide.

  2SO2+O2V2O52SO3ΔrHo=−196.6kJ

The reaction is reversible and exothermic.

(3) Sulphur trioxide is dissolved in 98% sulphuric acid to form oleum (fuming sulphuric acid). 

  SO3+H2SO4→H2S2O7

(4) Oleum is diluted with water to form sulphuric acid of desired concentration.

    H2S2O7+H2O→2H2SO4

            and

Manufacture of H2SO4 by contact process involves three steps:

1. Burning of sulphur in air to generate SO2.

2. Conversion of SO2 to SO3 by oxidation with air in the presence of 

A

Carbon monoxide gas can be prepared in lab by heating formic acid or oxalic acid with conc. H2SO4.

Procedure: Small amount of oxalic acid crystal is taken in a round- bottomed flask and all the apparatus are fitted as shown in figure. When conc. H2SO4 is poured in the flask through thistle funnel and heated then a mixture of CO and CO2 gas is formed. The mixture of gas is passed through a bottle containing NaOH solution where the CO2 gas is absorbed by NaOH.

2NaOH + CO2 → Na2CO3 + H2O

The pure CO gas is then collected in a gas jar by downward displacement of water.

Answer:

for volume only liters can be used

Explanation:

Answer:

which energy?........

Explanation:

..........................

........

....

Answer:

Reducing sugars are sugars where the anomeric carbon has an OH group attached that can reduce other compounds. Non-reducing sugars do not have an OH group attached to the anomeric carbon so they cannot reduce other compounds. ... Maltose and lactose are reducing sugars, while sucrose is a non-reducing sugar

Answer:

They are good electrolytes

Answer:

Reproducible by other scientists

The personal opinion of the scientist

Using vanable conditions for each test

Explanation:

Answer:

helloooo

0.164m * 100 = 16.4 cm

now multiplying all of em

v = 1,687.888

Answer:

Is water the only liquid? If not, name 5 more

Water, ethanol, household bleach, blood, paint, milk, gasoline, mineral oil, acetone and butyl alcohol are examples of liquids. Liquids' properties allow them to flow or be poured easily into containers, lava

water is not the only liquid.

Answer:

apple juice, milk, smoothie, blood, urine

Answer:

(b) A and C belongs to same group.

(c) D is a non metal.

Explanation:

The Electronic Configuration of E is

[tex]1s {}^{2} 2s {}^{2}2p {}^{6} 3s {}^{2} 3p {}^{6} 4s {}^{2} [/tex]