The chart shows the bids provided by four contractors to complete a job. Which contractor is the most cost-effective? Joshua Carmen Dante Alicia

Answer:

D

Explanation:

because when some organisms will move from one place to another the number of population will decrease

Answer:

The correct option is option C

Explanation:

Loss or gain of electron(s) occurs in a type of attraction known as electrovalent or ionic attraction. In this type, there is transfer (or loss) of electron(s) from a metal atom to become positively charged while a nonmetal accepts (or gains) this electron to become negatively charged.

When this does not happen, two metal atoms can become attached by sharing the same electrons through a form of attraction known as covalent bonding. Here, the two atoms share electrons (known as shared pair) together to achieve there octet configuration on the outermost shell.  

Answer:

The correct answer is = 31.04

Explanation:

The relation between volume, temperature and pressure of a fix amount of a gas can be expressed by the combined gas law:

PV/T = k

It can be written as well as

P1V1/T1 = P2V2/T2

Given:

V1 = 217.6

P1 = 9.011 atm

T1 = 127.8°C = 400.95 K

P2 = 44.9

T2 = 11.9 °C = 285.05

Solution:

Putting value in the formula

V2 = P1V1T2/P2T1

= (217.6*285.05*9.011)/44.9*400.95

V2 = 31.04

Answer:

C. an element

Explanation:

Elements are pure substances and made up of only one type of atoms which cannot be further broken down.

Answer:

PCl5 <-> PCl3 + Cl2

PCl5 decomposes into PCl3 and Cl2 according to the equation above. A pure sample of Pcl5 is placed in a rigid, evacuated 1.00 L container. The initial pressure of the PCl5 is 1.00 atm. The temperature is held constant until the PCl5 reaches equilibrium with its decomposition products. The figures below show the initial and equilibrium conditions of the system.

As the reaction progresses toward equilibrium, the rate of the forward reaction

A) increases until it becomes the same as the reverse reaction rate at equilibrium

B) stays constant before and after equilibrium is reached

C) decreases to become a constant nonzero rate at equilibrium

D) decreases to become zero at equilibrium

Explanation:

At equilibrium, both forward and backward reactions take place with constant speed.

The reaction will never cease.

Due to this reason chemical equilibrium is called dynamic in nature.

At equilibrium:

the rate of forward reaction = rate of backward reaction

As the reaction progresses toward equilibrium, the rate of the forward reaction decreases to become a constant nonzero rate at equilibrium.

Answer is option C).

When a system is in a state of chemical equilibrium, neither the reactant concentration nor the product concentration changes over time, nor does the system exhibit any further changes in its attributes. Here the correct option is C.

The system reaches a condition of chemical equilibrium when the rate of the forward reaction equals the rate of the reverse reaction. The system is considered to be in a state of dynamic equilibrium when the concentrations of the reactants and products do not change further as a result of the equal rates of the forward and reverse processes.

Equilibrium is impacted by a number of variables, including temperature, pressure, and the system's concentration. Here at equilibrium the rate of the forward reaction decreases to become a constant nonzero rate at equilibrium.

Thus the correct option is C.

To know more about chemical equilibrium, visit;

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Answer:

? which question

Explanation:

Answer: The equilibrium will shift in the direction of [tex]NH_3[/tex]

Explanation:

The chemical equation for the aqueous solution of ammonia follows:

[tex]NH_3+H_2O\rightleftharpoons NH_4^++OH^-[/tex]

According to Le-chtelier's principle:

If there is any change in the variables of the reaction, then the equilibrium will shift in that direction of equilibrium to minimize the effect.

If we add more amount of [tex]NH_4^+[/tex] to the solution, more of the products will be present. But according to Le-chtelier's principle, to minimize this effect, the equilibrium will shift in the backward direction that in the direction of [tex]NH_3[/tex]

Hence, the equilibrium will shift in the direction of [tex]NH_3[/tex]

Answer:

Atomic number = 25 protons

Mass number = ( 25 + 30 ) = 55

Answer:

Calcium= 2,8,8,2

Potassium= 2,8,8,1

Answer:

Atomic number of potassium = 19

Therefore number of electrons = 19

Since, maximum number of electrons in outermost orbit will not be more than 8, thus the 19th electron of potassium atom will reside in 4th.

Thus, electronic configuration of potassium is

given in first pic.

Number of orbit in potassium = 4

Atomic number of calcium = 20

Therefore number of electrons = 20

Thus, electronic configuration of calcium is given in sec pic.

Number of orbit in calcium = 4

Explanation:

#keep learning!!

Answer:

Formula of EPSOM salt = MgSO4.7H2O

molecular mass of MgSO4.7H2O = atomic mass of Mg + atomic mass of S + 4 × atomic mass of O + 7 { 2 × atomic mass of H + atomic mass of O }

= 24 + 32 + 4× 16 + 7{ 2 × 1 + 16 } g/mol

= (24 + 32 + 64+ 126 ) g/mol

= 246 g/mol

molecular mass of total water = 7 × ( 2× atomic mass of H + atomic mass of O )

= 7 × 18 = 126 g/mol

now ,

% mass of H2O in EPSOM salt = {total molar mass of H2O/molar mass of Epsom salts }× 100

= {126/246 } × 100

= 12600/246

= 51.21 %

Explanation:

i have done it hope it helps

Answer:

the answer is C) higher concentration of water in the soil than in the root hairs

Explanation:

Answer:

the answer is c

Explanation:

i just got it

Answer:

what the--

Explanation:

pls tell one by one

Answer:

Sodium atoms due to being smaller in size have high ionization energy and thus, it can't lose electrons easily and is more stable and less reactive. ... Hence, from this it is clear that sodium is less reactive than potassium.

Explanation:

Answer:

The amount of water

The amount of sugar and

The amount of yeast

Explanation:

A constant variable is that variable in an experiment which must be kept the same for all groups in order not to alter the results of the experiment.

In this question, the independent variable i.e. the variable being manipulated is the TYPE OF SUGAR USED while the dependent variable i.e. variable that responds to change is AMOUNT OF ENERGY. Three different types of sugar were used viz: maltose, glucose, and sucrose. To not alter the outcome of the experiment, the constants of this experiment i.e. variables that must be the same for all groups of the experiment, include the following:

- The amount of water

- The amount of sugar

- The amount of yeast used

Answer:

Ionic compounds are crystalline solids, soluble in water and conduct electricity when molten or in solution. These characteristics are due to the type of link that holds them together.

Answer:

D.Protien

Explanation:

DNA has four nucleobases: adenine, thymine, guanine, and cytosine. The nucleobases in a DNA strand have preferred partners to form hydrogen bonds with. Cytosine pairs with guanine, and adenine pairs with thymine. These are the base pairing rules that allow DNA replication and protein synthesis to happen.

Answer:

Its the first one

Explanation:

4 mol is the highest of the Bunch and 4.0L is the lowest making the first answer the correct one

Answer:

because you are cxloser

Explanation:

There would be 9.03 x  [tex]10^{23}[/tex] particles in 13.5 grams of Beryllium.

Recall that 1 mole of a substance contains 6.02 x 10^23 atoms.

Number of moles in 13.5 grams of Beryllium = mass/molar mass

                    = 13.5/9

                       = 1.5 moles

Thus, total number of atoms in 1.5 moles Beryllium:

             = 1.5 x 6.02 x 10^23

                    = 9.03 x  [tex]10^{23}[/tex]

More on the number of particles in a substance can be found here: https://brainly.com/question/1445383

Answer:

SiH

Explanation:

The symbol for Silicon is Si, and the symbol for Hydrogen is H. There is no need for extra characters in the name.

Answer:

Alcohols are usually named by the first procedure and are designated by an -ol suffix, as in ethanol, CH3CH2OH (note that a locator number is unnecessary on a two-carbon chain). On longer chains the location of the hydroxyl group determines chain numbering. For example: (CH3)2C=CHCH(OH)CH3 is 4-methyl-3-penten-2-ol.10  

Explanation:

Answer:

ethanol formula :C2H5Oh

Answer:

4

4, because when there is no number after decimal then all the numbers are considered significant even 0 is the last number.

The complete question is as follows: 2 molecules of potassium chlorate (KClO3) form 2 molecules of potassium chloride (KCl) and 3 molecules of oxygen (O2). Write a balanced equation for this reaction?

Answer: The balanced chemical equation is [tex]2KClO_{3} \rightarrow 2KCl + 3O_{2}[/tex].

Explanation:

A balanced equation is defined as the equation which contains same number of atoms on both reactant and product side when a chemical reaction occurs.

Hence, when 2 molecules of potassium chlorate [tex](KClO_{3})[/tex] form 2 molecules of potassium chloride (KCl) and 3 molecules of oxygen [tex](O_{2})[/tex] then its balanced equation will be as follows.

[tex]2KClO_{3} \rightarrow 2KCl + 3O_{2}[/tex]

Here, number of atoms on the reactant side as as follows.

Number of atoms on the product side are as follows.

Since, the number of atoms on reactant side are equal to the number of atoms on product side. So, this reaction equation is balanced.

Thus, we can conclude that the balanced chemical equation is [tex]2KClO_{3} \rightarrow 2KCl + 3O_{2}[/tex].

Answer:

condensation

Explanation:

when heated beaker sed condensation

Answer: The equilibrium constant for the reverse reaction at the same temperature is [tex]2.40 \times 10^{33}[/tex].

Explanation:

The given reaction equation is as follows.

[tex]2HCl(g) \rightleftharpoons H_{2}(g) + Cl_{2}(g)[/tex] ... (1)

It's equilibrium constant (K) value is [tex]4.17 \times 10^{-34}[/tex].

Also, another reaction equation is as follows.

[tex]H_{2}(g) + Cl_{2}(g) \rightleftharpoons 2HCl(g)[/tex]

This is the reverse of equation (1). Hence, its equilibrium value is calculated as follows.

[tex]K' = \frac{1}{K}\\= \frac{1}{4.17 \times 10^{-34}}\\= 2.40 \times 10^{33}[/tex]

Thus, we can conclude that the equilibrium constant for the reverse reaction at the same temperature is [tex]2.40 \times 10^{33}[/tex].

Answer: