Which set of the below elements are in the same period.

1. Li, Be, C, O

2. H, Li, Be

3. F, CI, Br, I

4. H, He, Li, Be

Answer:

C. Na and F

Explanation:

The reaction between Sodium and fluorine will proceed more quickly and easily of all the given reaction choices.

This is because fluorine is the most electronegative element and sodium is more electropositive when compared to Lithium.

The heat of formation of nitrogen (II) oxide : +91.3 kJ/mol

Given

Reaction

N2(g) + O2(g) + 182.6 kJ → 2 NO(g)

Required

The heat of formation

Solution

In the above reaction, the heat of the reaction is located on the reactant side which indicates that the formation of nitric oxide requires heat (endothermic reaction).

In the above reaction the heat required to form 2 moles of NO, so the heat required for each mole is:

+182.6 kJ : 2 = =+91.3 kJ/mol

a. t = 4.33 s

b. R = 53.04 m

c. H = 22.97 m

Given

vo=initial velocity=24.5 m/s

Angle = θ = 60°

Required

(a) time of flight, (b) range, and (c) maximum height.

Solution

Parabolic motion

a. time to flight

t = (2vo sin θ) / g

t = (2 x 24.5 x sin 60) / 9.8

t = 4.33 s

b. range (horizontal range) :

R = (vo² sin2θ )/g

R =(24.5² sin 120)/9.8

R = 53.04 m

c. maximum height

H = (vo²sin²θ)/2g

H = (24.5²sin²60)/2.9.8

H = 22.97 m

The wavelength of the radiation : λ=5.792 x 10⁻⁸ m = 5.792 x 10⁻⁶ cm

Region of Ultraviolet

Given

A frequency : 5.18 x10¹⁵ Hz

Required

The wavelength

Solution

Frequency (f): the number of waves per second  

Wavelength (λ): the distance from one crest/one trough to another

Fast wave propagation (v): the distance traveled by waves per unit of time  

v= 3 x 10⁸ m/s

General formula :

v = λ.f

λ=v/f

Input the value :

λ=3.10⁸ : 5.18.10¹⁵

λ=5.792 x 10⁻⁸ m = 5.792 x 10⁻⁶ cm

Region of Ultraviolet (4000 - 10 A°, 4 x 10⁻⁵ - 10⁻⁷ cm,7.5 x 10¹⁴ - 3 x 10¹⁷ Hz)

Answer:

shivering is a natural bodily response, the body is trying to heat itself up by moving around.

Answer: addition and elimination

Explanation:

In addition you add and in elimination you remove (or subtract)

The reactions that are the reverse of one another are addition and elimination. Details about types of reactions are as follows.

A reaction is the transformation in which one or more substances is converted into another by combination or decomposition.

Reactions can be of different types as follows:

However, addition and elimination reactions are reverse of one another because addition involves adding substances while elimination involves removing substances.

Learn more about reactions at: https://brainly.com/question/17434463

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Answer: in the daytime the sun is out so the stars are not visible becuase the suns reflection! At night When you gaze at the constellations, every star produces an image that's the same size, but your retina isn't sensitive enough to respond to the outer parts of those images except for the brighter stars — which therefore look bigger than the fainter ones.

Explanation:

This is what I found on goog.le a while ago now it might actually help if I’m wrong I apologiz, I hope this was your quistion!

Answer:

87% bromine and 13% magnesium

Explanation:

The compound contained 32.0 grams of bromine and 4.9 grams of magnesium.

We need to find its percent composition.

Mass of the sample = mass of bromine + mass of magnesium

= 32 g + 4.9 g

= 36.9  g

Percentage composition of bromine,

[tex]\%=\dfrac{32}{36.9}\times 100\\\\=86.7\\\\=87\%[/tex]

The percentage composition of magnesium,

[tex]\%=\dfrac{4.9}{36.9}\times 100\\\\=13.27\\\\=13\%[/tex]

So, its percent composition is 87% bromine and 13% magnesium.

Answer:

O begins to boil

Explanation:

When the vapor pressure of a liquid is equal to the atmospheric pressure, the liquid suddenly begins to boil.

Answer:

has no observable changes

Explanation:

Explanation:

Homologous series are the series belonging to a series of aliphatic organic compounds that differ only by the addition of a CH2 group

Hope it will help :)❤

Answer:

3012.51×10²³ atoms of Ne

Explanation:

Given data:

Mass of Ne = 10090 g

Number of atoms = ?

Solution;

Formula:

Number of moles = mass/ molar mass

Molar mass of Ne = 20.17 g/mol

Number of moles = 10090 g/ 20.17 g/mol

Number of moles = 500.25 mol

Number of atoms:

1 mole contain 6.022×10²³ atoms

500.25 mol × 6.022×10²³ atoms / 1 mol

3012.51×10²³ atoms

Answer - The substance that is produced from a chemical reaction....

REACTANTS

Answer:

f = 0.94 ×10²⁴  Hz

Explanation:

Given data:

Frequency of light = ?

Wavelength of light = 3.2 ×10⁻¹⁶ m

Solution:

Formula:

Speed of light = wavelength × frequency

c = λ × f

c = speed of wave = 3×10⁸ m/s

by putting values,

3×10⁸ m/s  = f × 3.2 ×10⁻¹⁶ m

f  =  3×10⁸ m/s   / 3.2 ×10⁻¹⁶ m

f  = 0.94 ×10²⁴ s⁻¹

f = 0.94 ×10²⁴  Hz (Hz = s⁻¹)

Answer:

Answer at the bottom

Explanation:

A Be

B Li

C Mg

D Nahe answered their bottom

Answer:

Explanation

whats your question

Answer:

B. They are highly reactive.

Explanation:

Answer:

B: They are highly reactive

Explanation:

Sodium(Na) and potassium(K) are in the same family/group which is the Alkali Metal group.  These groups have their ability to displace H2(g) from water and create a basic solution. Alkali metals are also known to react violently and explosively with water. This is because enough heat is given off during the exothermic reaction to ignite the H2(g). Therefore, they are similar because of their reactivity.

Hope I helped!

Answer:

B  29 protons, 27 electrons

Explanation:

The given specie is copper ion:

         Cu²⁺  

We are to find the number of protons and electrons it contains.

 The number of protons is the positively charged particles in the atom.

 Electrons are the negatively charged particles in the atom.

The number of protons is the same as the atomic number

Atomic number of copper  = 29

 Number of protons  = 29

 Now;

    Charge  = Number of protons  - Number of electrons

     2  = 29  - number of electrons

     -27  = - number of electrons

 Number of electrons  = 27

Answer:

The ranking of matter from the LEAST amount of energy to MOST amount of energy is;

B. Solid, Liquid, Gas

Explanation:

The kinetic energy of the particles that make of matter depends on the temperature of the particles and the particles are constantly vibrating

Solid state (Least amount of energy)

In the solid state, the matter is held in solid (rigid) crystal lattice and the particles are rigidly located next to other adjacent particles and stacked up layer by layer

Liquid state (Intermediate amount of energy)

As the temperature of the particles are increased by heating, the particles (atoms and molecules) gain more kinetic energy and their vibration is increased which on further heating, leads to the breaking of the lattice bond of the solid state and the particles are then readjusted to exist side by side rather than being stacked on one another and the assume the liquid state

Upon further heating the particles in the liquid acquire more energy and are  and rather than exist side-by-side, they are able to exist as individual particles in the gaseous form

Gaseous state (Most amount of energy)

From the kinetic theory of matter, the molecules of matter in the gaseous state contains enough energy which is more than the intermolecular forces of attraction such that the particles are able to move and occupy the entire volume of the container in which it is placed

Therefore, the correct option is Solid, Liquid, Gas.

Answer:

gas > liquid > solid

Explanation:

Because I said so,

And I took the test.

Answer:

392g

Explanation:

The given compound is;

         Cr₂(SO₄)₃

To find the molar mass, we sum the atomic masses of the elements in the compounds together.

Atomic mass of Cr  = 52

                           S  = 32

                            O  = 16

So;

 Molar mass  = 2(52) + 3[32 + 4(16)]  = 392g/mol

%yield = 88.5%

Given

Reaction

Cu(s) + 2 AgNO₃(aq) → Cu(NO₃)₂(aq) + 2Ag(s)

Required

The percent yield

Solution

mol AgNO₃(MW=169,87 g/mol) :

= mass : MW

= 127 : 169.87

= 0.748

mol Ag from equation :

= 2/2 x mol AgNO₃

= 2/2 x 0.748

= 0.748

Mass Ag (theoretical) :

= mol x Ar Ag

= 0.748 x 108

= 80.784

% yield = (actual/theoretical) x 100%

%yield = 71.5/80.784 x 100%

%yield = 88.5%

hope this answer helps and have a good day

Answer:

Mass = 29.23 g

Explanation:

Given data:

Volume of solution = 814.2 mL 814.2/1000 = 0.8142 L)

Molarity of solution = 0.227 M

Mass of solute in gram = ?

Solution:

Molarity = number of moles / volume in L

By putting values,

0.227 M = number of moles / 0.8142 L

Number of moles = 0.227 M × 0.8142 L

Number of moles = 0.184 mol

Mass in gram:

Mass = number of moles × molar mass

Molar mass of calcium acetate = 158.17 g/mol

Mass = 0.184 mol × 158.17 g/mol

Mass = 29.23 g

Answer:

it will transverse wave I think it will help you

Answer:

either first or second if not them try d but I'm pretty sure a also I'm sorry if I getbyou this wrong I dearly apologize