What evidence supports the law of conservation of energy?

Light energy is converted to chemical energy during photosynthesis.
Oxygen is made from the breakdown of carbon dioxide during photosynthesis.
Energy is absorbed by chlorophyll during photosynthesis.
The sun gives off light energy that is absorbed by plants.

Answer: The number of series in Mendeleev's Periodic table is 12.

Explanation:

Horizontal rows present in the periodic table are called periods. Vertical rows in the periodic table are called series.

Mendeleev gave periodic table in the year 1869 by arranging elements according to their atomic weights a in tabular form.  

Mendeleev's periodic table depicts 12 periods/series.

Thus, we can conclude that the number of periods/series in Mendeleev's Periodic table is 12.

Answer:

the molar mass of the element

Answer:

That is a " ball and stick " model which represents carbon compounds.

Explanation:

This is the answer. Hope it helps you find what you're looking for.

Answer:

Explained below.

Explanation:

In order to extract lead from lead oxide, we need to add carbon from coke to the lead oxide.

We will need;

A bunsen burner

A test tube

Charcoal

First step is to heat charcoal in an oxygen free environment. The safety measure here to ensure an oxygen free environment is to add some zinc metal powder into the test tube in order to remove any atmospheric oxygen inside the container.

Secondly, we will now put charcoal inside the test tube and turn on the bunsen burner to heat it until coke is formed.

Thirdly, we now introduce lead oxide into the coke inside the test tube and the carbon in the coke reacts with the lead oxide to produce lead and carbon dioxide.

Throughout all this process, since we required an oxygen free environment inside the test tube, whenever the test tube is opened, its neck must immediately be warmed by heat with the tube placed in a horizontal direction or very close to being in that horizontal direction so that any movement of air moves outwards from the tube.

Answer:

The equivalent weight of calcium hydroxide is 1/2 he mass of a mol of calcium hydroxide. 1 mol Ca(OH)2 = 74 grams Ca(OH)2 ; 1 equivalent Ca(OH)2 = 37 grams Ca(OH)2......

Explanation:

HOPE IT HELPS YOU

Answer:

option a

hope helps you

have a great day

Answer:

the product is Mg(Clo3)2 + AgI

Answer:

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Answer:

That is, the atom is a solid and indivisible mass. However, the fenomenom by which an iron atom emits particles when it is struck by light (known as the photoelectric effect) can not be explaind by this indivisible atom model.

Explanation: The hypothesis is a prediction, but it involves more than a guess. Most of the time, the hypothesis begins with a question which is then explored through background research. It is only at this point that researchers begin to develop a testable hypothesis.

(Unless you are creating an exploratory study, your hypothesis should always explain what you expect to happen)

Answer:

It has a negative charge and is located in orbitals around the nucleus

Explanation:

The statement describes an electron is " It has a negative charge and is located in orbitals around the nucleus."

The electron would be a subatomic particle with a negatively one elementary charge electric charge.

Protons, that have a positive charge, as well as neutrons, which have no electrical charge, make up the nucleus. Quarks were subatomic particles that make up protons but also neutrons.

Electrons were present surrounding the atom's nucleus, in contrast to protons as well as neutrons, that are contained within the nucleus at its core. Negative electrons were drawn to the positive nucleus since the electric charges of opposite polarity attract one another.

To know more about electrons and nucleus.

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Answer:

64 g

Explanation:

Step 1: Write the balanced equation

2 Na + Cl₂ ⇒ 2 NaCl

Step 2: Calculate the moles corresponding to 25 g of Na

The molar mass of Na is 22.98 g/mol.

25 g × 1 mol/22.98 g = 1.1 mol

Step 3: Calculate the moles of NaCl formed from 1.1 moles of Na

The molar ratio of Na to NaCl is 2:2. The moles of NaCl formed are 2/2 × 1.1 mol = 1.1 mol.

Step 4: Calculate the mass corresponding to 1.1 moles of NaCl

The molar mass of NaCl is 58.44 g/mol.

1.1 mol × 58.44 g/mol = 64 g

Answer:

To 318.18 mL would you need to dilute 20.0 mL of a 1.40 M solution of LiCN to make a 0.0880 M solution of LiCN

Explanation:

Dilution is the reduction of the concentration of a chemical in a solution and consists simply of adding more solvent.

In a dilution the amount of solute does not vary. But as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.

In a solution it is fulfilled:

Ci* Vi = Cf* Vf

where:

In this case:

Replacing:

1.40 M* 20 mL= 0.088 M* Vf

Solving:

[tex]Vf=\frac{1.40 M* 20 mL}{0.088 M}[/tex]

Vf= 318.18 mL

To 318.18 mL would you need to dilute 20.0 mL of a 1.40 M solution of LiCN to make a 0.0880 M solution of LiCN

Answer:

3.36 grams Al°(s)  

Explanation:

Given AlCl₃(s), determine the mass (grams) of Al°(s) produced from electrolysis of Aluminum Chloride at 10.0 amps for 1.00 hour.

AlCl₃(s) + 378.3°F (=192.4°C) => Al⁺³(l) + 3Cl⁻(l)

formula wt. Al° = 27g/mol

Faraday Constant (F°) = 96,500 amp·sec

? grams Al°(s) = 10.0amps x (1 mole e⁻/96,500amp-sec) x (1 mole Al°(s)/3 mole e⁻) x (27g Al°(s)/1 mole Al°(s)) x 3,600 sec = 3.36 grams Al°(s)

The 3.36 grams of aluminum are produced in 1 hour by the electrolysis of molten AlCl₃ when 10A current is passed.

Electrolysis is a process that uses an electrical current to break chemical compounds. The electric current is passed through the substance to bring the chemical change by gain or loss of electrons.

The electrolysis of the aluminum chloride in the molten state is represented as:

AlCl₃  →   Al³⁺    +  3Cl⁻

At cathode:   Al³⁺  +  3e⁻  →  Al (s)

Given,  the current. I = 10 A and  t = 1 hr = 3600 s

We know that the current is calculated from the equation:  I = q/t

q = I× t

q = (10A) × (3600s)

q = 36 × 10³ C

We know, 96500 C of the charge has electrons = 1 mol

36 × 10³ C of the charge has electrons  = 0.373 mol

3 moles of electrons required to produce aluminum = 1 mol

0.373 mol of electrons will produce aluminum = 0.373/3 = 0.124 mol

We know that, the mass of one mole of Al = 27g

The mass of 0.124 mol of Al = 27 × 0.124 = 3.36 g

Therefore, the aluminum produced in 1 hour by the electrolysis of molten AlCl₃ is equal to 3.36 grams.

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Answer: The correct option is ALL OF THE ABOVE.

Explanation:

TITRATION is a type of volumetric analysis which is used for determining the concentration of solutions. In this process a specific volume of a solution is placed in a conical flask by means of a pipette and small quantities of a second solution is slowly added from a burette until the end point is reached. This is determined by a means of an indicator which shows a characteristic colour change.

During titration, the following precautions should be followed to avoid errors and maintain standardisation in the experiment.

--> Any air bubble in the burette and pipette must be removed during measurement

--> the burette tap should be tightened to avoid leakage.

--> Remove the funnel from the burette before taking any reading to avoid errors in reading the volume.

--> use the base solution such as Sodium Hydroxide Solution to rinse the burette after washing with soap and tap water:

• to remove any air bubble and fill it's tip

• to remove any residual liquid from the water and soap solution which may interfere with the results of the experiment.

• to check if the burette is in good condition.

Therefore all of the above options to the question are correct.

Answer:

(a) The potential near its surface is 45 * 10^6 V.

(b) The distance from which its center is the potential 1.00 MV is 45 m.

(c) Its energy in MeV when the atom is at the distance found in part b is 132 MeV.

Explanation:

Note: This question is not complete. The complete question is therefore provided before answering the question.

A research Van de Graaff generator has a 2.00-m diameter metal sphere with a charge of 5.00 mC on it. (a) What is the potential near its surface?

(b) At what distance from its center is the potential 1.00 MV?

(c) An oxygen atom with three missing electrons is released near the Van de Graaff generator. What is its energy in MeV when the atom is at the distance found in part b?

The explanation of the answer is now provided as follows:

(a) What is the potential near its surface?

Q = Charge on the generator = 5 mC = 5 * 10^(-3)C

r = Sphere radius = 2 / 2 = 1 m

k = Constant of the electric force = 9 * 10^(9) N . m^2 / C^2

Therefore, the electric potential of a point charge can be calculated as follows:

V = kQ / r

V = (9 * 10^9 * 5 * 10^(-3)) / 1 = 45 * 10^6 V

Therefore, the potential near its surface is 45 * 10^6 V.

(b) At what distance from its center is the potential 1.00 MV?

This implies the distance where the potential is 1 MV.

Since the electric potential of a point charge is as follows:

V = kQ / r

Therefore, we can solve for r and estimate it as follows:

R = kQ / V = (9 * 10^9 * 5 * 10^(-3)) / 1 * 10^6 = 45 m

Therefore, the distance from which its center is the potential 1.00 MV is 45 m.

(c) An oxygen atom with three missing electrons is released near the Van de Graaff generator. What is its energy in MeV when the atom is at the distance found in part b?

The link between the potential difference and electrical potential energy can be stated as follows:

ΔV = ΔU / q

Therefore, we have:

ΔU = qΔV = q(Va - Vb) = 3 * (45 – 1) = 132 MeV

Therefore, its energy in MeV when the atom is at the distance found in part b is 132 MeV.

Answer:

21.6 g

Explanation:

The reaction that takes place is:

First we convert the given masses of both reactants into moles, using their respective molar masses:

0.6 moles of CH₄ would react completely with (2 * 0.6) 1.2 moles of O₂. As there are more O₂ moles than required, O₂ is the reactant in excess and CH₄ is the limiting reactant.

Now we calculate how many moles of water are produced, using the number of moles of the limiting reactant:

Finally we convert 1.2 moles of water into grams, using its molar mass:

Answer:

For 1: The product is phosphoric acid and the solution is acidic in nature.

For 2: The product is sodium hydroxide and the solution is basic in nature.

For 3: The product is nitric acid and the solution is acidic in nature.

Explanation:

For the given options:

(1): When diphosphorus pentoxide reacts with water, it leads to the formation of phosphoric acid, which makes the solution acidic in nature.

The chemical equation for the reaction follows:

[tex]P_4O_{10}+6H_2O(l)\rightarrow 4H_3PO_4(aq)[/tex]

(2): When disodium oxide reacts with water, it leads to the formation of sodium hydroxide, which makes the solution basic in nature.

The chemical equation for the reaction follows:

[tex]Na_2O+H_2O(l)\rightarrow 2NaOH(aq)[/tex]

(3): When dinitrogen pentoxide reacts with water, it leads to the formation of nitric acid, which makes the solution acidic in nature.

The chemical equation for the reaction follows:

[tex]3N_2O_5+3H_2O(l)\rightarrow 6HNO_3(aq)[/tex]

Answer: If a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.

Explanation:

The relation between energy and wavelength is as follows.

[tex]E = \frac{hc}{\lambda}\\[/tex]

This means that energy is inversely proportional to wavelength.

As it is given that energy of a hydrogen atom and a helium atom is same.

Let us assume that [tex]E_{hydrogen} = E_{helium} = E'[/tex]. Hence, relation between their wavelengths will be calculated as follows.

[tex]E_{hydrogen} = \frac{hc}{\lambda_{hydrogen}}[/tex]    ... (1)

[tex]E_{helium} = \frac{hc}{\lambda_{helium}}[/tex]         ... (2)

Equating the equations (1) and (2) as follows.

[tex]E_{hydrogen} = E_{helium} = E'\\\frac{hc}{\lambda_{hydrogen}} = \frac{hc}{\lambda_{helium}} = E'\\\lambda_{helium} = \lambda_{hydrogen} = E'[/tex]

Thus, we can conclude that if a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.

Answer:

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ASAP PROJECT

Answer:

a. [tex]Ag^0[/tex]

b. [tex]Ag^{+}[/tex]

c. [tex]Ca^{2+}F_2^-[/tex]

d. [tex]H_2^+S^{2-}[/tex]

e. [tex](C^{4+}O_3^{2-})^{-}[/tex]

f. [tex](Cr^{6+}O_4^{2-})^{2-}[/tex]

g. [tex]Cl_2^0[/tex]

h. [tex]Fe^0[/tex]

i. [tex]Cu^{2+}Cl_2^-[/tex]

j. [tex]C^{4-}H_4^+[/tex]

Explanation:

Hello there!

In this case, according to the concept of charge balance, which tell us that the overall charge is zero for any compound, except ions, it turns out possible to proceed as follows:

a. [tex]Ag^0[/tex]

b. [tex]Ag^{+}[/tex]

c. [tex]Ca^{2+}F_2^-[/tex]

d. [tex]H_2^+S^{2-}[/tex]

e. [tex](C^{4+}O_3^{2-})^{-}[/tex]

f. [tex](Cr^{6+}O_4^{2-})^{2-}[/tex]

g. [tex]Cl_2^0[/tex]

h. [tex]Fe^0[/tex]

i. [tex]Cu^{2+}Cl_2^-[/tex]

j. [tex]C^{4-}H_4^+[/tex]

Keep in mind lonely elements have 0 as their oxidation state.

Regards!

Answer:

Danger

Explanation:

Answer:

 Lewis structure of Hydronium ion is shown below :                          

Explanation:

Lewis structure : It is a representation of valence electrons on the atoms in a molecule

Here , Hydronium ion is given , which contains 1 atom of oxygen and 3 atoms of hydrogen .

Oxygen has a total of 6 valence electrons and hydrogen contains 1 valence electron .

Oxygen share its 3 valence electrons with 3 hydrogen atoms and left with 3 valence electrons. From these three valence  electrons of oxygen atom  two electrons will be shown as a pair of electrons on oxygen atom but a single electron can not be shown . So , to simplify this, one positive charge is shown overall .  

Resonance structure will be same as the hybrid structure because all  three atoms are same , that is hydrogen .

Answer:

0.5024 g

Explanation:

Step 1: Calculate the concentration of H⁺

We will use the definition of pH.

pH = -log [H⁺]

[H⁺] = antilog -pH = antilog -12.40 = 3.981 × 10⁻¹³ M

Step 2: Calculate the concentration of OH⁻

We will use the ionic product of water expression.

[H⁺] [OH⁻] = 10⁻¹⁴

[OH⁻] = 10⁻¹⁴/[H⁺] = 10⁻¹⁴/3.981 × 10⁻¹³ = 0.02512 M

Step 3: Calculate the initial concentration of NaOH

NaOH is a strong base and the molar ratio of NaOH to OH⁻is 1:1. Thus, the initial concentration of NaOH is 1/1 × 0.02512 M = 0.02512 M.

Step 4: Calculate the moles of NaOH

We will use the definition of molarity.

M = moles of NaOH/liters of solution

moles of NaOH = M × liters of solution

moles of NaOH = 0.02512 mol/L × 0.5000 L = 0.01256 mol

Step 5: Calculate the mass of 0.01256 moles of NaOH

The molar mass of NaOH is 40.00 g/mol.

0.01256 mol × 40.00 g/mol = 0.5024 g

Answer:

Towards the big bully

Explanation:

If a big bully and a small child are involved in a thug of war, it is clear that the bully is stronger than the child and he/she will pull the rope used in the thug of war with a greater force.

By so doing, the ball attached at the centre of the rope will naturally be drawn towards the stronger bully.

Answer:

The full amount (5.00 g) will be dissolved in 1 L of water at 25°C.

Explanation:

The molecular weight (MW) of Vanillin (C₈H₈O₃) is calculated from the chemical formula as follows:

MW(C₈H₈O₃) = (12 g/mol x 8) + (1 g/mol x 8) + (16 g/mol x 3) = 152 g/mol

If 0.070 mol of C₈H₈O₃ are soluble per liter of water at 25°C, the maximum mass that can be dissolved in 1 L is:

0.070 mol x 152 g/mol = 10.64 g

Since 5.00 g is lesser than the maximum amount that can be dissolved (10.64 g), the added amount will be completely dissolved in 1 L of water at 25°C.

Answer:

SN1 mechanism

Explanation:

The mechanism of this reaction is shown in the image attached.

The Di- n- pentyl ether is first protonated. The CH3(CH2)4OH is now a good leaving group as shown.

The attack of the bromide ion on the cation formed completes the mechanism to yield 1- bromopentane as shown in the mechanism.

Answer:

By how many times would you expect Al2(SO4)3 to depress the F.P of water compared to sucrose C12H22011 ?.

Explanation:

The freezing point of a pure solvent decreases further by adding a nonvolatile solute.

This is called depression in freezing point.

When an ionic solute is dissolved then the depression in the freezing point is proportional to the number of ions present in the solution.

In aluminum sulfate, there are five ions formed as shown below:

[tex]Al_2(SO_4)_3(aq)->2Al^3^+(aq)+3SO_4^2^-(aq)[/tex]

But sucrose is a covalent compound and it does not undergo dissociation.

Hence, aluminum sulfate decreases the freezing point of water by five times compared to sucrose.

Explanation:

Answer:

118.06 mL

Explanation:

The neutralization reaction between HBr (acid) and Ba(OH)₂ (base) is the following:

2HBr + Ba(OH)₂ → BaBr₂ + 2H₂O

According to the equation, 2 moles of HBr react with 1 mol Ba(OH)₂. Thus, at the equivalence point the moles of acid and base react completely:

2 moles HBr = 1 mol Ba(OH)₂

We can replace the moles by the product of the molar concentration (M) and volume (V):

2 x (M HBr) x (V HBr) = M Ba(OH)₂ x V Ba(OH)₂

Now, we introduce the data in the equation to calculate the volume in mL of Ba(OH)₂:

V Ba(OH)₂ = (2 x (M HBr) x (V HBr))/M Ba(OH)₂

                 = (2 x 0.311 M x 57.7 mL)/(0.304 M)

                 = 118.06 mL

Therefore, 118 mL of Ba(OH)₂ are needed.