who established the two important laws of chemical combination combination state them​

Answer: 51.9961 g/mol, don't know if it helps :)

Explanation:

Answer:

Chromium is a steel-gray, lustrous, hard metal that takes a high polish, is fusible with difficulty, and is resistant to corrosion and tarnishing.

The most common oxidation states of chromium are +2, +3, and +6, with +3 being the most stable. +4 and +5 are relatively rare. Chromium compounds of oxidation state 6 are powerful oxidants.ion:

Factors that affect the strength of electromagnets are the nature of the core material, strength of the current passing through the core, the number of turns of wire on the core and the shape and size of the core.

Answer:

an effect could be that the battery could be running out of juice or that there isnt enough wire on a nail on the electromagnet.

Explanation:

Answer:

D. when the number of moles of acid is exactly equal to the number of moles of base.

Explanation:

Regarding options A. and E., pKa and pKb would only be taken into consideration if the titrations were of weak acids and bases. However it is possible to have a titration of monoprotic acids and bases with strong acids and bases.

Another way of looking at the answer is identifying which one best describes the equivalence point.

The coefficient for Br and OH has been 3 and 6 respectively. Thus option C is correct.

If the reaction takes place in a basic medium, the reaction can be given as:

[tex]\rm Br_2\;+\;OH^-\;\rightarrow\;BrO_3^-\;+\;Br\;+H_2O[/tex]

The coefficient has been placed in the chemical reaction to balance the number of atoms on the product and the reactant side.

The number of atoms of Br on the product side has been 2, and the reactant side has been 2.

The oxygen atoms have been 1 on the reactant side, and 3 on the product side.

It has been balanced as:

[tex]\rm 3\;Br_2\;+\;6\;OH^-\;\rightarrow\;BrO_3^-\;+\;5\;Br^-\;+\;3\;H_2O[/tex]

The coefficient for Br and OH has been 3 and 6 respectively. Thus option C is correct.

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Answer:

4

Explanation:

The Balmer series refers to a series of spectral emission lines of the hydrogen atom arising from electronic transitions from any higher level and terminating at the the energy level n= 2.

Using the relation;

1/λ = 1.09737*10^7 (1/2^2 -1/n^2initial)

We now have;

1/486 *10^-9 = 1.09737*10^7 (1/2^2 -1/n^2initial)

0.1875 = 1/2^2 -1/n^2initial

1/n^2initial = 1/2^2 - 0.1875

1/n^2initial = 0.0625

n^2initial = 16

ninitial = 4

Answer:

The answer is "[tex]\bold{1.39 \ mg}[/tex]".

Explanation:

Please find the complete question in the attached file.

Total Moles of [tex]Mg_2^{+}[/tex] = moles of [tex]MgSO_4[/tex]

                                 [tex]= \frac{mass}{molar \ mass \ of MgSO_4}\\\\= \frac{0.450}{120.37}\\\\ = 0.0037385 \ mol[/tex]

[tex]Mg_2^{+} + EDTA4^{-} \longrightarrow Mg(EDTA)2^{-}[/tex]

EDTA mol in 37.6 mL of solution = 50.0 mL of [tex]Mg2^{+}[/tex]

                                                      [tex]= \frac{50.0}{500} \times[/tex] total moles of [tex]Mg2^{+}[/tex]

                                                      [tex]= \frac{50.0}{500} \times 0.0037385\\\\= 3.7385 \times 10^{(-4)} \ mol\\[/tex]

[tex]Ca2^{+} + EDTA4^{-} \longrightarrow Ca(EDTA)2^{-}[/tex]

[tex]CaCO_3 Moles = Ca2^{+} Moles =[/tex] EDTA moles in a solution of 1.40 mL

                      [tex]= \frac{1.40}{37.6} \times 37.6 \ mL[/tex] the solution of EDTA moles.

                      [tex]= \frac{1.40}{37.6} \times 3.7385 \times 10^{(-4)} \\\\= 1.392 \times 10^{(-5)}\ mol\\\\[/tex]

Mass of [tex]CaCO_3 =[/tex]mole[tex]\times[/tex] the molar mass of [tex]CaCO_3[/tex]

                            [tex]= 1.392 \times 10^{(-5)} \times 100.09\\\\= 0.00139 \ g\\\\ = 1.39 \ mg[/tex]

Answer:

The reaction is 2F_2 (g) + 2H_2 O (g) rightarrow 4HF (g) + O_2 (g) 2 moles of fluorine gas (F_2) reacts with 2 moles of water vapors (H_2 O) to produce 4 moles of hy

Answer:

z = 2s

Explanation:

This is the only info given.

Answer:

The percent yield would be 73%

Explanation:

The balanced reaction for the obtention of acetylsalicylic acid (aspirin) is the following:

Salicylic acid + acetic anhydride → acetylsalicylic acid + acetic acid

C₇H₆O₃          +          C₄H₆O₃        →         C₉H₈O₄           +    C₂H₄O₂

According to the reaction, 1 mol of salicylic acid reacts with 1 mol of acetic anhydride to give 1 mol of acetylsalicylic acid (aspirin) and 1 mol of acetic acid.

1 mol aspirin (C₉H₈O₄) = (9 x 12 g/mol) + (8 x 1 g/mol) + (4 x 16 g/mol)

                                     = 180 g

1 mol salicylic acid (C₇H₆O₃) = (7 x 12 g/mol) + (6 x 1 g/mol) + (3 x 16 g/mol)

                                              = 138 g

1 mol acetic anhydride (C₄H₆O₃) = (4 x 12 g/mol) + (6 x 1 g/mol) + (3 x 16 g/mol)

                                                      = 102 g

The stoichiometric ratio is = 138 g salicylic acid/102 g acetic anhydride= 1.35

We have:

2.0 g salicylic acid

acetic anhydride = 5.0 mL x 1.08 g/mL = 5.4 g

The reactants ratio is = 2.0 g salicylic acid/5.4 g acetic anhydride = 0.37

0.37 < 1.35 , therefore salicylic acid is the limiting reactant.

Now, we use the amount of salicylic acid to calculate the theoretical amount of aspirin. For this, we know that 1 mol of aspirin (180 g) is obtained from 1 mol of salycilic acid (138 g):

theoretical yield= 180 g aspirin/138 g salycilic acid x 2.0 g salycilic acid = 2.61 g aspirin

actual yield = 1.9 g

Finally, we calculate the yield:

percent yield = actual yield/theoretical yield x 100

        = 1.9 g/2.6 g x 100 = 72.8% ≅ 73%

Answer:

Creativity leads scientists to design new methods to test their hypotheses.

Creativity permits scientists to think of new questions to investigate.

Explanation:

A scientist must be very creative and must be a critical thinker.

Creativity is the ability of someone to use imaginations to solve a problem.

Answer:

B and D

Explanation:

Answer:

5.74 L O₂

General Formulas and Concepts:

Chemistry - Gas Laws

Explanation:

Step 1: Define

RxN:   2HgO (s) → 2Hg (s) + O₂ (g)

Given:   111 g HgO

Step 2: Identify Conversions

STP

Molar Mass of Hg - 200.59 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of HgO - 200.59 + 16.00 = 216.59 g/mol

Step 3: Stoichiometry

[tex]111 \ g \ HgO(\frac{1 \ mol \ HgO}{216.59 \ g \ HgO} )(\frac{1 \ mol \ O_2}{2 \ mol \ HgO} )(\frac{22.4 \ L \ O_2}{1 \ mol \ O_2} )[/tex] = 5.73988 L O₂

Step 4: Check

We are given 3 sig figs. Follow sig fig rules and round.

5.73988 L O₂ ≈ 5.74 L O₂

Answer:

If you're talking about Solid, Liquid, and Gas the answer would be... well I'm not gonna give this to you straiight away but, here's a game! It has at least 5 letters in it...It has the letter I in it, It has a S in it Hope you got the answer! ✨Brainliest pwease!

Answer:

C.

Explanation:

They will need to know the influence of gravitational force on objects because gravity can affect an objects weight.

Answer:

In the given case, to get a blue flame, one should open the air inlet further. To increase the size of the flame one should open the gas regulator further. When one opens the air inlet, more amount of oxygen goes within, and thus, one can get a more intense form of blue flame.

When one opens the gas regulator more concentration of gas goes and the larger the size of flame one gets.

To regulate a bunsen burner follow this procedure

To get a blue flame, you should rotate the wheel  of the burner anticlockwise further to reduce the level of oxygen flow.

To increase the size of the flame, you should rotate the wheel clockwise further

The bunsen burner is an apparatus in the laboratory used to carry out experiment when heating of substance is required, hence it is used to add heat to substances, it has a wheel used to regulate the flow of air which is required for combustion, it has a hose which is used to tap gas to the burner

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Answer:

Of the main group elements, fluorine has the highest electronegativity (EN = 4.0) and cesium the lowest (EN = 0.79). This indicates that fluorine has a high tendency to gain electrons from other elements with lower electronegativities.

Explanation:

Answer:

H3PO4 + 3NaOH ==> Na3PO4 + 3H2O

The balanced equation for the given reaction is [tex]3NaOH+H_3PO_4---- > Na_3PO_4+3H_2O[/tex]

A chemical reaction in which an acid and a base react quantitatively with each other is known as neutralization.

In a water reaction, neutralization means that there is no excess of hydrogen or hydroxide ions in the solution.

A neutralization reaction occurs when an acid and a base react to form water and a salt through the combination of H+ ions and OH- ions. The pH of neutralization of a strong acid and a strong base is 7.

Three moles of sodium hydroxide are required for one mole of phosphoric acid. The balanced equation tells us the following: 1 mol of H3PO4 reacts with 3 mol of NaOH.

It can be written as

[tex]3NaOH+H_3PO_4---- > Na_3PO_4+3H_2O[/tex]

Thus, this is the balanced equation for the given neutralizing reaction.

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#SPJ2

Answer:

270 mL

Explanation:

First we convert the child's weight to kg:

So the total mass of morphine sulfate that should be injected is:

Finally we calculate the volume that should be injected, using the concentration of the available solution:

The accurate millilitre is 268 mL.

First of all, we must obtain the mass of the child in kilograms;

1 Ib = 0.45 Kg

85 lb = 85 lb × 0.45 Kg/1 Ib

= 38.25 Kg

If 1 Kg takes 35.0 mcg/kg/dose

38.25 Kg takes 38.25 Kg × 35.0 mcg/kg/dose/1 Kg

= 1338.75 mg/dose

Hence;

1338.75 mg/dose/5.0-mg/mL  = 268 mL

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Answer:

A

Explanation:

Based on the arrows, the direction the air masses are moving is from west

to east.

These contains large volume of air which has a uniform temperature and

humidity. Air masses move in the atmosphere through the process known

as Convection.

The movement of the air tells us that the movement is from  the Western

part to the Eastern part of the atmosphere.

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Answer:

The answer is "Option e"

Explanation:

The ionic bond arousal system of the outer shells (VSEPR) allows us to determine which one of the feasible solutions are found in the majority of instances. It's also supposed to occupy the space with electrical pairs and also to reduce electrical couple repulsive forces to a minimum, its cheapest electricity framework. This theory can be used for predicting a form of electron pairs with a different mass of a particle's core electrons.

Answer:

The emmision of ionizing radiation or particles caused by the spontaneous disintegration of atomic nuclei

or

the giving off of rays of energy or particles by the breaking apart of atoms of certain elements

Answer:

The correct answer is 0.020 atm.

Explanation:

Partial pressure is calculated by using the formula,

Partial pressure = Mole fraction × Total pressure

The partial pressure of oxygen in a mixture can be calculated by using the formula,  

Mole fraction of oxygen in mixture = Number of moles of oxygen / No. of moles of oxygen + No. of moles of Helium

(1 gg or gigagram is equal to 10⁹ grams)

= 2 × 10⁹/32 /2 × 10⁹/32 + 98 × 10⁹ / 4

= 2.54 × 10⁻³

Now the partial pressure of oxygen = Mole fraction of oxygen × Total pressure of oxygen

= 2.54 × 10⁻³ × 8.0 atm

= 0.02032 atm

= 0.020 atm

Answer:

Explanation:

1) Pure substance: Water (found at home)

Appearance: It is homogeneous since it is a single substance that appears as liquid. Homogeneous is when the components of a substance are in a single phase

Separating technique: It's component cannot be separated by physical means

Boiling point: Water boils at 100 °C

Melting point: Water melts/freezes at 0°C

2) Pure substance: Table salt (found at home)

Appearance: It is also homogeneous as it is a single substance that is solid. Separating technique: It's component cannot be separated by physical means

Boiling point: Water boils at 1,465 °C

Melting point: Water melts/freezes at 801 °C

3) Pure substance: Butter (found at home and grocery store)

Appearance: It is homogeneous even though it contains different components

Separating technique: It's component can be separated by physical means since butter is an emulsion of fat in water. The 15% water content can be evaporated/distilled out at 100 °C

Boiling point: Butter starts boiling at about 110-120 °C

Melting point: It melts at about 37 °C

4) Pure substance: Candle (wax) (found at home and grocery store)

Appearance: It is homogeneous

Separating technique: It's component cannot be separated by physical means

Boiling point: It starts boiling around 370 °C

Melting point: It melts at about 37 °C

5) Pure substance: table sugar/sucrose (found at home, grocery stores and in supermarkets)

Appearance: It is homogeneous

Separating technique: It's component cannot be separated by physical means

Boiling point: It starts boiling around 697 °C

Melting point: It melts at about 186 °C

A pure substance is an homogeneous material, having a composition, and

properties that are consistent through out the material.

The chemical properties of a pure substance are defined, such as the

products of its reaction can be predictable.

A chemical is pure when it consist of a single type of particle such as an

element, a molecule or a compound.

The five pure substances are presented as follows;

[tex]\displaystyle\begin{tabular}{|l|l|l|l|l|}\underline{Pure \ Substances}&\underline{Appearance}&\underline{Separaing Tech}&\underline{Boiling \ Point}&\underline{Melting \ point}\\1. Diamond&Translucent \ solid&Inseparable&3550^{\circ}&4830^{\circ}\\2. Table \ salt&White\ crystals&Insepble&801^{\circ}&1413^{\circ}\\3. Water&Tran parent \ liquid&Insepble&0^{\circ}&100^{\circ}\\4. Sugar&Whilte \ crystals&Heating&Decomposes&186^{\circ}\\5. Gold&Yellowish \ metal&Inseparable& 2700^{\circ}&1064^{\circ}\end{array}[/tex]

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Answer:

Mega = 10^6

Milli = 10^-3

Explanation:

Mega is whatever times 10 to 6th power.

Milli is whatever times 10 to the -3rd power.

Answer:

[tex]7.22 \times 10^{23}e^{-}[/tex]

[tex]1.16 \times 10^{5}C[/tex]

Explanation:

Step 1: Write the reaction for the electrochemical reduction of copper.

Cu²⁺(aq) + 2 e⁻ → Cu(s)

Step 2: Calculate the number of electrons required in the reduction of 0.600 moles of Cu²⁺

We will use the following relationships:

[tex]0.600molCu^{2+} \times \frac{2mole^{-} }{1molCu^{2+} } \times \frac{6.02 \times 10^{23}e^{-} }{1mole^{-}} = 7.22 \times 10^{23}e^{-}[/tex]

Step 3: Calculate the Coulombs corresponding to [tex]7.22 \times 10^{23}e^{-}[/tex]

We will use the following relationships:

[tex]7.22 \times 10^{23}e^{-} \times \frac{1 mol e^{-}}{6.02 \times 10^{23}e^{-}} \times \frac{96486C}{1 mol e^{-}} =1.16 \times 10^{5}C[/tex]

Answer:

The cell potential = +0.03 V

Explanation:

The half reactions for the cells are given below:

Oxidation half reaction (anode):   Zn(s) ----> Zn²⁺(aq) + 2e⁻

Reduction half reaction (cathode):  Zn²⁺(aq) + 2e⁻ -----> Zn(s)

To calculate cell potential of the cell, we use the equation given by Nernst, which is given as: Ecell = E°cell - (0.0591/n) log Q

where  Q = Concentration of dilute solution/Concentration of concentrated solution = 0.01/0.1

n = number of moles of electrons transferred = 2

Since, the cell is a concentration cell, E°cell = 0

therefore, the Nernst equation becomes, Ecell = - (0.0591/n) log Q

substituting the values;

Ecell = - (0.0591/2) log (0.01/0.10)

Ecell = +0.03 V

Therefore, the cell potential = +0.03 V

Answer:

See explanation

Explanation:

According to Bohr's theory, when external energy is supplied to an atom, its electrons absorb energy and move from a lower energy level to a higher energy level.They quickly return to their original level and re-radiate the absorbed energy as a photo of light.

Hence, when an atom in ground state receives external energy, it becomes excited because energy is transferred to its electrons and they move from lower to higher energy level.

The electron after getting the energy would jump to an orbital further away from the nucleus.  

• Ground state refers to the lowest energy state an atom can be at. When an electron in an atom captivates energy it is considered to be in an excited state.  

• An excited atom becomes unstable and seem to align itself to move back to its lowest energy state.  

• When an atom in its ground state is supplied with an external energy, the energy is absorbed by the atom and the electron becomes excited and jumps to an orbit , that is, distant from the nucleus.  

• It can be said that electron attains higher energy state, with the absorption of more energy by the atom, the electron further moves to higher state till it becomes a free electron and no longer remains the part of the atom.  

Thus, the electron after getting the energy would jump to an orbital further away from the nucleus.

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Answer:

C The atoms has a tiny, massive nucleus at its center with electrons surrounding it

Explanation:

From the experiment by Rutherford, he suggested a model of the atom where there is a tiny but massive nucleus at the center with electrons surrounding it.

Answer:

4,2,3,1

Explanation:

Answer:

a) When air inside the tires gets colder, it shrinks, so the tires seem flat, even though they haven't lost any air.

b) When the air inside the soda can gets hot, the molecules of gas move faster, exerting more and more and more pressure, eventually exploding the soda can.

c) When the nalgene is cooled, the air pressure inside will lower; the volume of the nalgene will stay the same, though, because the nalgene is a rigid container.

Given :

A seawater sample contains 2.7 mg chlorophyll m⁻³.

To Find :

What is the chlorophyll concentration in units of mg L⁻¹.

Solution :

We know, 1 m³ = 1000 L .

So, 1 m⁻³ = 10⁻³ L⁻¹

Concentration is :

[tex]c = 2.7\ mg\ m^{-3}\\\\c = 2.7\times 10^{-3}\times \ mg\ L^{-1}\\\\c = 0.0027 \ mg\ L^{-1}\\\\c = 2.7\ \mu g \ L^{-1}[/tex]

Therefore, the chlorophyll concentration in units of mg L⁻¹ is [tex]2.7\ \mu g \ L^{-1}[/tex].

Hence, this is the required solution.