Question 12 of 32
The work of which scientist was most essential to the use of the scientific
method and quantitative measurements in chemistry?
A. Antoine-Laurent Lavoisier
B. John Dalton
O C. Robert Boyle
O D. Marie Curie

Answer:

Kinetic energy of electron = -E₂ = 3.4 ev

Kinetic energy of electron = -E₄ = 0.85 ev

Explanation:

In case of hydrogen atom energy associated with nth state is,

En =  -13.6/n²

For n = 2

E₂ = -13.6 / 2²

E₂ = -13.6/4

E₂ = -3.4 ev

Kinetic energy of electron = -E₂ = 3.4 ev

For n = 4

E₄ = -13.6 / 4²

E₄ = -13.6/16

E₄ = -0.85 ev

Kinetic energy of electron = -E₄ = 0.85 ev

Explanation:

For the two samples, the mass and volume of the foil are different but irrespective of this, the density of the aluminum foil will remain the same.

Mass depends on the amount of matter present and as given in the description, the sample with a high number has more mass.

Volume is the amount of space a substance occupy.

Answer:

amount of matter

Explanation:

Answer:

[tex]Amount\ of\ Grams = 0.2644 g[/tex]

Explanation:

Given

Element: Sodium

[tex]Atoms = 6.92 * 10^{21}[/tex]

Required

Determine the amount of grams

We start by solving for the number of moles

[tex]Moles = \frac{Sodium\ Atoms}{Avogadro\ Number}[/tex]

[tex]Avogadro\ Number = 6.022 * 10^{23}[/tex]

So, we have:

[tex]Moles = \frac{6.92 * 10^{21}}{6.022 * 10^{23}}[/tex]

[tex]Moles = \frac{6.92 * 10^{21-23}}{6.022}[/tex]

[tex]Moles = \frac{6.92 * 10^{-2}}{6.022}[/tex]

[tex]Moles = 1.15 * 10^{-2}[/tex] moles

Next, we calculate the amount of grams.

Mass per mol of Sodium = 22.98977g/mol

For [tex]1.15 * 10^{-2}[/tex] moles of sodium

[tex]Amount\ of\ Grams = 1.15 * 10^{-2}\ mol * 22.98977g/mol[/tex]

[tex]Amount\ of\ Grams = 1.15 * 10^{-2} * 22.98977g[/tex]

[tex]Amount\ of\ Grams = 0.264382355 g[/tex]

[tex]Amount\ of\ Grams = 0.2644 g[/tex] (approximated)

Hence, there are 0.2644g of sodium in [tex]6.92 * 10^{21}[/tex] atoms

Answer: The correct formula is [tex]MgBr_2[/tex]

Explanation:

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.  

Here magnesium is having an oxidation state of +2 called as [tex]Mg^{2+}[/tex] cation and bromine [tex]Br^{-}[/tex] is an anion with oxidation state of -1. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral [tex]MgBr_2[/tex].

The cations and anions being oppositely charged attract each other through strong coloumbic forces and form an ionic bond.

Answer:

Power and Nuclear Fision

Answer:

the variable A represented specific heat capacity

Answer: The Variable T

Explanation:

The mass of the silver : 4.6 g

Heat can be calculated using the formula:  

Q = mc∆T  

Q = heat, J  

m = mass, g  

c = specific heat, joules / g ° C  

∆T = temperature difference, ° C / K  

∆T = temperature difference :

[tex]\tt 46-22=24^oC[/tex]

The specific heat of silver is  0.235 J/gºC

Q = heat = 26 J

The mass :

[tex]\tt mass(m)=\dfrac{Q}{c.\Delta T}\\\\m=\dfrac{26}{0.235\times 24}\\\\m=4.6~g[/tex]

Answer:

Ksp = 2.74 x 10⁻⁵

Explanation:

The solubility equilibrium for Ca(OH)₂ is the following:

  Ca(OH)₂(s) ⇄ Ca²⁺(aq) + 2 OH⁻(aq)

I                          0                0

C                       + s               + 2s

E                        s                   2s

According to the ICE table, the expression for the solubility product constant (Kps) is:

Ksp = [Ca²⁺] x ([OH⁻])² = s x (2s)² = 4s³

Then, we calculate Ksp from the solubility value (s):

s = 0.019 M

⇒ Ksp = 4s³ = 4 x (0.019)³ = 2.74 x 10⁻⁵

The Ksp value of Ca(OH)2 is [tex]2.74 \times 10^-^5[/tex].

The Ksp is the solubility product constant.

The solubility equilibrium is

[tex]Ca(OH)_2(s) = Ca^2^+(aq) + 2 OH^-(aq)[/tex]

I                     0                  0

C                     s               +2s

E                     s                 2s

By the ICE table, the expression for Ksp is

[tex]\rm Ksp = [Ca^2^+] \times ([OH^-])^2 = s \times (2s)^2 = 4s^3[/tex]

Now, calculate the Ksp

s, solubility value is 0.019 M

then, [tex]\rm Ksp = 4s^3= 4 \times (0.019)^3 = 2.74 \times 10^-^5[/tex]

Thus, the Ksp value is [tex]2.74 \times 10^-^5[/tex]

Learn more about Ksp

https://brainly.com/question/27132799

Answer:

Air is a mixture. Its constituents can be separated. For example: oxygen, nitrogen etc.

Hydrochloric acid is a mixture, being an acidic liquid.

Answer:

You could observe the cell wall in all kingdoms except for the animals. That would be cells of plants, protists (algae), fungi, bacteria and achaea.

Answer:

i think a or b

Explanation:

Answer:

100

Explanation:

nsvcscjkvschssvds

Answer:

I THINK IT MIGHT  BE B

Explanation:

Answer:

Electricity is made at a generating station by huge generators. The current is sent through transformers to increase the voltage to push the power long distances.  The electrical charge goes through high-voltage transmission lines that stretch across the country.

Answer:

in parallel

Explanation:

All of the home equipment in the residence are linked in parallel.

parallel association

electric appliances are connected in a parallel arrangement in a house circuit because every appliance gets complete voltage as resistance in a parallel association is low.

electric appliances are not linked in series because the cutting-edge can be the same thru all the home equipment connected but voltage increases if extra no. Of appliances are related. If the battery has low voltage than the full voltage it can short circuit.

research greater approximately the parallel.

Learn more about parallel circuit

here:https://brainly.com/query/12069231

#SPF2

Answer:

the lava viscosity defines the size and shape of a volcano. Even though lava is 100,000 times more viscous than water, it can still flow great distances. When lava has low viscosity, it can flow very easily over long distances. This creates the classic rivers of lava, with channels, puddles and fountains.

Answer:

B) It will decrease because fewer particles will have the required activation energy.

Explanation:

Temperature is one of the important factors that affect the rate of a chemical reaction. An increase in the temperature of a reaction will cause the reactants to gain more kinetic energy and hence, reduce the energy required for reactants collision (start) to occur i.e. activation energy.

Note that, once the activation energy is reduced, the rate of reaction is increased. In this case, the temperature of a reaction vessel with liquid reactants is lowered to one-third (1/3) of the original temperature. Due to a reduction in the reaction's temperature, the rate of reaction will also decrease because fewer particles will have the required activation energy.

Answer:

B. It will decrease because fewer particles will have the required activation energy.

Explanation:

I took the text :)

Answer:

brainly

Explanation:

Adjust your day-to-day behaviors.

Replace your light bulbs.

Use smart power strips.

Install a programmable or smart thermostat.

Purchase energy efficient appliances.

Answer:

The correct option would be 'electrons

Explanation:

Answer:

there is 7 periods and 18 groups

Explanation:

Answer:

HF is an acid as it losses hydrogen into the sollution on hydrolysis.

Explanation:

The answer is 87.62 u

Answer:

Atomic number: 38

Electrons per shell: 2,8,18,8,2

Symbol: Sr

Answer:

Nitrogen-15

Explanation:

To use the correct notation, you need to use the mass number.  The mass number is the number of protons plus the number of neutrons.  Nitrogen has 7 protons.  This isotope of nitrogen has 8 neutrons.

The correct notation is nitrogen-15.

Answer:

4. Another element is formed with greater atomic number​

Explanation:

Ions only have a different amount of electrons and have the same amount of protons and neutrons.

Isotopes only have a difference in neutrons.

However, only a difference in protons will make another element.

Hence, 4 is the answer.

Hope this helped!

It ISNT occurs in substances that have discrete molecular structure

Explanation:

I took the test and got this wrong

Answer:

V = 29.3 inch³

Explanation:

Given data:

Diameter of cone = 4 inch

Height of cone = 7 inch

Volume of cone = ?

Solution:

Formula:

V = πr²h/3

we calculate the radius from diameter,

r = 4 inch/2 = 2 inch

Volume:

V = 3.14 ×(2 inch)²  × 7 inch/3

V = 3.14 × 4 inch² × 7 inch/3

V = 29.3 inch³

Strong bases are bases which completely dissociate in water into the cation and OH- (hydroxide ion). The hydroxides of the Group I (alkali metals) and Group II (alkaline earth) metals usually are considered to be strong bases. These are classic Arrhenius bases. Here is a list of the most common strong bases.

LiOH - lithium hydroxide

NaOH - sodium hydroxide

KOH - potassium hydroxide

RbOH - rubidium hydroxide

CsOH - cesium hydroxide

*Ca(OH)2 - calcium hydroxide

*Sr(OH)2 - strontium hydroxide

*Ba(OH)2 - barium hydroxide

A strong base has been indicated with the ability to be a good conductor of electricity. Hence, option B is correct.

Bases are defined as compounds that have the ability to form the release of the negative ions or the hydroxide ions in the solution. The acids release hydrogen or proton, thereby bases tend to have the ability to neutralize acids.

The pH has been the measure of the solution to be able to accept or donate the protons and electrons. The pH has been measured on a scale of 1-14 with the acids having a pH of less than 7, and the pH of bases tends to move towards 14. 7 is the neutral pH.

The strong bases form the dissociation of the ions in the solution more readily, and ions contribute as the medium, thereby forming the conduction of the electricity. Hence, option B is correct.

Learn more about base here:

https://brainly.com/question/27739836

#SPJ5

Explanation:

Atomic radius decreases from left to right in a period.

Therefore Calcium would have a smaller atomic size.