Please help immediately it’s due today

Answer:

false.nowadays humans are destroying forest,extracted more minerals,making pollution. in my view.

Answer:

Yes this is true

Explanation:

Answer:

i have the same question for chemistry, do you have the answer?

Explanation:

Answer:

2000 m

Explanation:

From the question given above, the following data were:

Elevation (m) >>>>>> Temperature (°C)

4000 >>>>>>>>>>>>> –8

3500 >>>>>>>>>>>>> –4

3000 >>>>>>>>>>>>> 0

2500 >>>>>>>>>>>>> 4

Temperature = 8 °C

Elevation =?

A careful observation of the table shows that:

Elevation is reducing with 500 m, while the temperature is increasing with 4 °C.

Next, we shall determine number of increase in the temperature. This can be obtained as follow:

Last Temperature from the table = 4 °C

New temperature = 8 °C

Difference = 8 °C – 4 °C

Number of Increase = difference / 4 °C

Number of Increase = 4 °C / 4 °C

Number of Increase = 1

Thus, the temperature increased just ones from 4 °C to 8 °C

Since the temperature increased just ones from 4 °C to 8 °C, it means the elevation will decrease just ones i.e

Last elevation from the table = 2500 m

Decrease factor = 500 m

New elevation = 2500 – 500

New elevation = 2000 m

Thus, the temperature (i.e 8 °C) was recorded at an elevation of 2000 m

This question is not complete, the complete question is;

Calculate the final pH of a solution made by the addition of 10 mL of a 0.5 M NaOH solution to 500 mL of a 0.4 M HA originally at pH  = 5.0 ( pKa = 5.0)

Neglect the volume change.

Options:

a) 6.10

b) 5.09

c) 7.00

d) 5.02

Answer:

the final pH of a solution is 5.02

Option d) 5.02 is the Correct Answer

Explanation:

Given the data in the question,

Initially pKa = pH; so ratio is 1:1

thus, 0.4 M acid and base

Now, moles of NaOH = molarity × volume = 0.5 × 10 = 5 mmol = 5 × 10⁻³ mol.

Going into 500 mL ( 0.5 L ) of solution

new molarity will be;

⇒ moles / volume = 5 × 10⁻³ / 0.5 = 0.01 M

ACID reacting with BASE

original concentration of acid = 0.4 - 0.01 = 0.39 M

original concentration of base = 0.4 + 0.01 = 0.41 M

so

pH = 5 + log( base/acid)

= 5 + log ( 0.41/0.39)

= 5 + log ( 1.0512)

= 5 + 0.021

pH = 5.02

Therefore the final pH of a solution is 5.02

Option d) 5.02 is the Correct Answer

Answer:

Explanation:

The first process is to draw out the heating curve to have a look at the transition possible which we've shown in the file below.

Now;

To find the energy removed to convert 75g steam → ice then comparing it with 215 kJ.

So conversion of steam at 125 °C → 100 °C

[tex]\Delta H = (75 \ g) (2.0 \ J/g^0C ) (125 - 100)^0 \ C[/tex]

[tex]\Delta H = 3750 \ J[/tex]

[tex]\Delta H = 3.75 \ kJ[/tex]

Since this is lesser than the energy given  (215 kJ), we then have to find the energy removed in the next phase.

For condensation of steam

Find the energy removed to change the steam from 100° C to liquid  at 100° C

[tex]\Delta H_2 = ( \dfrac{75 \ g}{18.02 \ g/mol}) (40.7 \ kJ/mol)[/tex]

[tex]\Delta H_2 =1.690* 10^ 2 \ J[/tex]

[tex]\Delta H_2 =169 \ kJ[/tex]

The total energy that is now removed from the system is:

[tex]\Delta H_1+ \Delta H_2 = (169 + 3.75) \ kJ[/tex]

[tex]\Delta H_1+ \Delta H_2 \simeq 173 \ kJ[/tex] which is still lesser than 215 kJ

To the third step; which is the conversion of water at 100° C → water at 0° C

[tex]\Delta H_3 = ( 75 \ g) (4.2 \ J/g^0 C)(100-0)^0C[/tex]

[tex]\Delta H_3 = 31500 \ J[/tex]

[tex]\Delta H_3 = 31.5 \ kJ[/tex]

Thus;

[tex]\Delta H_1+\Delta H_2+\Delta H_3 = (169 + 3.75 +31.5) \ kJ[/tex]

[tex]\Delta H_1+\Delta H_2+\Delta H_3 =204 \ kJ[/tex]

To the fourth step;

For freezing of water; we need to find the energy removed to change the water at 0° C → ice at 0° C

[tex]\Delta H_4 = (\dfrac{75 \ g}{18.02 \ g/mol})(6.02 \ kJ/mol)[/tex]

[tex]\Delta H_4 = 25.1 \ kJ[/tex]

∴

To change to the solid phase at 0° C; the total energy that is being removed from the steam is  

[tex]\Delta H_1+\Delta H_2+\Delta H_3 +\Delta H_4 =(169 + 3.75 + 31.5 +25.1) \ kJ[/tex]

[tex]\Delta H_1+\Delta H_2+\Delta H_3 +\Delta H_4 =229 \ kJ[/tex]

Here, the calculated total energy is more than the given energy 215 kJ.

This implies that the water is not fully converted to ice when 215 kJ of energy removal occurs, Hence the two phases that exist are liquid and solid.

Answer:

[tex]m=69.3kg[/tex]

Explanation:

Hello!

In this case, since the density is computed by dividing the mass of the substance by its occupied volume (d=m/V), we first need to realize that 0.8206 g/mL is the same to 0.8206 kg/L, which means we first need to compute the volume in L:

[tex]V=22.3gal*\frac{3.78541L}{1gal}=84.415L[/tex]

Then, solving for the mass in d=m/V, we get m=d*V and therefore the mass of gasoline in that full tank turns out:

[tex]m=0.8206g/L*84.415L\\\\m=69.3kg[/tex]

Best regards!

Answer:

Sanitize

Explanation:

Answer:

- the central atom is usually the atom with the lowest subscript in the molecular formula and the atom that can form the most bonds. If all of the atoms usually form the same number of bonds, the least electronegative atom is usually the central atom.

- molecular shape (the shape that a single molecule has) is important in determining how the molecule interacts and reacts with other molecules. Molecular shape also influences the boiling point and melting point of molecules. If all molecules were linear then life as we know it would not exist.

The decay product represented by X : Thorium (Th) : ²³⁴₉₀Th

Given

Decay reaction

²³⁸₉₂U ⇒ ⁴₂He + X

Required

The decay product

Solution

Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,  

In a decay reaction, the sum of the mass number and atomic number of the elements in the reactants and products must be the same

So the mass number of the element X = 238 - 4 = 234

Atomic number of the element X = 92 - 2 = 90

If we look at the periodic system, then the element with atomic number 90 is Thorium (Th)

Answer:

The molar mass of carbon

Explanation:

Before the mass (in grams) of two moles of carbon can be determined, the molar mass of the element would be needed.

This is because the number of mole of an element is the ratio of its mass and the molar mass. That is,

number of mole = mass/molar mass

Hence, the mass of elements can be obtained by making it the subject of the formular;

mass = number of mole x molar mass

Therefore, the molar mass of carbon would be needed before the mass of 2 moles of the element can be determined.

Answer:

Zero with the subscripts, +2 without them.

Explanation:

Hello!

In this case, since we consider that two silicon are bonded with four oxygen atoms to form silicon oxide according to the following chemical equation:

[tex]Si^{4+}+O^{2-}\rightarrow Si_2O_4[/tex]

It is also possible to realize it can be simplified to obtain:

[tex]SiO_2[/tex]

Which means that the total charge with the subscripts is zero, and without the subscripts +2 (+4-2).

Best regards!

Answer:

the five major branches of chemistry are organic, inorganic, analytical, physical, and biochemistry.

Answer:

Hey..! I know only 1st one answer

Answer:

have lower boiling points than alcohols of similar molecular weights.

Explanation:

Alkenes are hydrocarbons of the general molecular formula CnH2n. Alkenes are nonpolar hydrocarbons that are insoluble in water.

We must recall that alcohols are able to associate in water due to hydrogen bonding. This causes alcohols to have a relatively higher boiling point than alkenes of comparable molecular weight. Hencethe answer above.

Answer:

Molarity of a solution = 0.3 mol/liter

Explanation:

Given:

Moles of solute = 15 moles

Amount of solution = 50 liters

Find:

Molarity of a solution

Computation:

Molarity of a solution = Moles of solute / Amount of solution

Molarity of a solution = 15 / 50

Molarity of a solution = 0.3 mol/liter

Answer:It is number 4

Explanation:

Answer:

56.04 g

Explanation:

Step 1: Given data

Moles of nitrogen (n): 2 mol

Step 2: Calculate the molar mass of nitrogen (M)

The molar mass of the molecule is the sum of the masses of the molecules that form it.

mN₂ = 2 × mN = 2 × 14.01 g/mol = 28.02 g/mol

Step 3: Calculate the mass corresponding to 2 moles of nitrogen

We will use the following expression.

m = n × M

m = 2 mol × 28.02 g/mol = 56.04 g

Answer:

8

Explanation:

The atomic mass of an atom refers to the number of protons in the nucleus of an atom. Hence, an element with 6 valence electron mean that it has 6 electrons in its outermost shell.

The atomic Number of elements with 6 valence electrons cannot necessarily be the same, however, elements with 6 valence electrons belong to group six on the periodic table.

From the options given above, :

Atomic number of 8 :

Configuration : 2, 6

Atomic number of 10 :

Configuration : 2, 8

Atomic number of 12 :

Configuration : 2, 8, 2

Hence, only the element with atomic number of 8 has 6 valence electrons in its outer most shell, hence, the answer.

Answer:

More slowly than

Larger than

Weaker

Explanation:

The vapor pressure of a solution describes how quickly a solution will turn into vapour. If we say that a solution has a high vapour pressure, we are actually saying that the solution turns into vapour more quickly.

Acetone has a higher vapour pressure than water so acetone turns to vapour quicker than water.

Vapour pressure has a lot to do with the magnitude of intermolecular forces in solution. The stronger the magnitude of intermolecular forces, the lower the vapor pressure and the more slowly the solution evapourates.

So, the hydrogen bonds in water provides stronger intermolecular forces than dispersion and dipole interaction in acetone. Hence, water vaporizes more slowly than acetone.

Answer:

sodium phosphide

Explanation:

Answer: 20.0 g of hydrogen chloride must simultaneously be formed

Explanation:

The balanced chemical reaction is :

[tex]NH_4Cl\rightarrow NH_3+HCl[/tex]

According to the law of conservation of mass, mass can neither be created nor be destroyed. The mass on reactant side must be equal to the mass on product side.

Thus mass of reactants = mass of products

Given : mass of ammonium chloride = mass of reactants = 29.4 g

mass of ammonia = 9.4 g

mass of products = mass of ammonia + mass of hydrogen chloride

9.4 g +mass of hydrogen chloride = 29.4 g

mass of hydrogen chloride = 20.0 g

Answer:

it takes two hydrogen atoms for every oxygen atom to produce this reaction, so the mole ratio between hydrogen and oxygen is 2:1

Answer:

[tex]1.214\ g[/tex]

Explanation:

[tex]We\ know\ that,\\No.\ of\ molecules\ of\ Hydrobromic\ acid=9.03*10^{21} HBr\ molecules\\Now,\\We\ know\ that\ Hydrobromic\ acid\ is\ constituted\ by\ 1\ Hydrogen\ molecule\\ and\ 1\ Bromine\ molecule.\\Gram\ Atomic\ Mass\ of\ Bromine \approx 80\ g\\Gram\ Atomic\ Mass\ of\ Hydrogen =1\ g\\Hence,\\The\ Gram\ Molecular\ Mass\ Of\ Hydrobromic\ Acid=1*1+1*80=81\ g\\Avagadro's\ Constant=6.022*10^{23}\ particles[/tex]

[tex]Now,\\We\ know\ that,\\Mass=\frac{No.\ of\ particles}{Avagadro's\ Constant}*GMM\\Here,\\Mass\ of\ 9.03*10^{21} molecules\ of\ HBr= \frac{9.03*10^{21}}{6.022*10^{23}}*81 \approx 1.214\ g[/tex]

Explanation:

Heat is transferred by conduction when adjacent atoms vibrate against one another or electrons move from one atom to another . Conduction is the most significant meanings of heat transfer within a solid or between solid objects informal contact.

Answer:

neutral!

pH = 7

Explanation:

⁄(⁄ ⁄•⁄ω⁄•⁄ ⁄)⁄

Answer:

Collision theory states that the rate of a chemical reaction is proportional to the number of collisions between reactant molecules. The more often reactant molecules collide, the more often they react with one another, and the faster the reaction rate.

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