Cells can regulate different processes in two ways. They can turn on and off the genes that make enzymes, or they can

A)

increase the activation energy of a reaction.

B)

increase the amount of energy needed to carry out the preferred process.

C)

regulate the enzymes that are already made.

D)

decrease the amount of energy needed to carry out the preferred process.

Answer:

Ozone layer depletion is the thinning of the ozone layer present in the upper atmosphere. This happens when the chlorine and bromine atoms in the atmosphere come in contact with ozone and destroy the ozone molecules. One chlorine can destroy 100,000 molecules of ozone. It is destroyed more quickly than it is created

Answer:

Ozone depletion, gradual thinning of Earth’s ozone layer in the upper atmosphere caused by the release of chemical compounds containing gaseous chlorine or bromine from industry and other human activities. The thinning is most pronounced in the polar regions, especially over Antarctica. Ozone depletion is a major environmental problem because it increases the amount of ultraviolet (UV) radiation that reaches Earth’s surface, which increases the rate of skin cancer, eye cataracts, and genetic and immune system damage. The Montreal Protocol, ratified in 1987, was the first of several comprehensive international agreements enacted to halt the production and use of ozone-depleting chemicals. As a result of continued international cooperation on this issue, the ozone layer is expected to recover over time.

Answer:

The change in concentration of H+ ions is -9.99×10⁻⁵

Explanation:

When pH rises, we talk about neutralization and, there is a decline in proton's concentration.

pH lower than 7 is acid

pH higher than 7 is basic

Protons are neutralized by hydroxides to make water as this:

H₃O⁺   +  OH⁻  ⇄   H₂O

pH = - log [H₃O⁺]

[H₃O⁺] = 10^-pH

In conclussion: [H₃O⁺]₁ = 10⁻⁴ → 1×10⁻⁴

[H₃O⁺]₂ = 10⁻⁷ → 1×10⁻⁷

1×10⁻⁷- 1×10⁻⁴

The change in concentration of H+ ions is -9.99×10⁻⁵

Answer: The number of moles of excess reagent left is 0.750 moles

Explanation:

The number of moles is calculated by using the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of [tex]KI[/tex] = 249 g

Molar mass of [tex]KI[/tex] = 166 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of KI}=\frac{249g}{166g/mol}=1.5mol[/tex]

Given mass of [tex]Pb(NO_3)_2[/tex] = 496.5 g

Molar mass of [tex]Pb(NO_3)_2[/tex] = 331 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of }Pb(NO_3)_2=\frac{496.5g}{331g/mol}=1.5mol[/tex]

The given chemical equation follows:

[tex]2KI+Pb(NO_3)_2\rightarrow 2KNO_3+PbI_2[/tex]

By stoichiometry of the reaction:

If 2 moles of KI reacts with 1 mole of lead(II) nitrate

So, 1.5 moles of KI will react with = [tex]\frac{1}{2}\times 1.5=0.75mol[/tex] of lead(II) nitrate

As the given amount of lead(II) nitrate is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.

Thus, KI is considered a limiting reagent because it limits the formation of the product.

Moles of excess reactant ([tex]Pb(NO_3)_2[/tex]) left = [1.5 - 0.75] = 0.750 moles

Hence, the number of moles of excess reagent left is 0.750 moles

Answer:

The boiling point of heavy water is 101.4C

please mark me brainlest pls

Answer: 101.42 Celsius

Explanation:

The boiling point of heavy water is 101.42 Celsius which is higher than the boiling point of normal water (100 Celsius)due to its higher molar mass

Answer:

B

Explanation:

B

endothermic

requires energy to occure

Answer:

333.3mL

Explanation:

Using the formula as follows:

C1V1 = C2V2

Where;

C1 = initial concentration (M)

C2 = final concentration (M)

V1 = initial volume (mL)

V2 = final volume (mL)

According to the information provided in this question,

C1 = 4.00M

C2 = 1.50M

V1 = 125mL

V2 = ?

Using C1V1 = C2V2

4 × 125 = 1.5 × V2

500 = 1.5V2

V2 = 500/1.5

V2 = 333.3mL

Therefore, the CuSO4 solution needs to be diluted to 333.3mL to make 1.50 M solution.

Considering the definition of alkanes, single bonds are found in an alkane.

Alkanes are a class of hydrocarbons (compounds containing only carbon and hydrogen) that are made up of a variable number of carbon atoms joined together by single bonds. In turn, each carbon atom bonds to hydrogen atoms, which may eventually be replaced by other atoms or functional groups.

In other words, alkanes are open or closed chain molecules that are linked by simple bonds.

Alkanes are saturated hydrocarbons because the bonds between carbon atoms are simple and stable. And as mentioned, the hydrogen atoms bonded to each carbon atom can be replaced by other atoms, such as halogens (fluorine, bromine, chlorine) or various groups or “radicals”. In the latter case, the structure becomes more complex giving rise to branched alkanes.

In summary, single bonds are found in an alkane.

Learn more about alkanes:

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Answer: C) single only

Explanation:

just got it right

Answer:

Metals:

1. Metals are strong than non metals

2. Metals can be formed in wires, thin sheets, utensils and any other heavy meachinary for industries.

3. Metals are used for building construction and used in many other manufacturers

Non Metals:

1. Non metals are less stronger than metals.

2. Non metals can be used for manufacturing bottles, toys, bags, files etc.

3. Non metals are used in making of bottles, jars, chairs etc.

Thank you.....

Have a good day.....

Answer:

so in one mole of atom there are 6.02×10^23.

answers to B is 2.41×10^24

Explanation:

use this equation

number of particle=moles X 6.02×10^23

=4 X 6.02 ×10^23

=2.41×10^24

hope this make sense:)

The number of particles present in 4 moles of a substance is 24.088 particles.

Moles is a unit to express the amount of any substance and in one mole of any substance 6.022 × 10²³ particles of that substance are present and this number is known as Avogadro's number.

As in 1 mole = 6.022 × 10²³ particles are present

In 4 moles = 4 × 6.022 × 10²³ = 24.088 particles are present

Hence, 24.088 particles are present in 4 moles.

To know more about Avogadro's number, visit the below link:
https://brainly.com/question/10614569

Answer:

here hope it helps

Explanation:

covalent bonds

Answer:

6000 ml

Explanation:

1 liter is a 1000 ml

Answer:

Sugar was the solute and water was the solvent.

Answer:

1. 43.44g of HCl

2. 26.67 L of HCl

Explanation:

1) Molarity of a solution = number of moles (n) ÷ Volume (V)

According to the provided information in this question,

V = 350 mL = 350/1000 = 0.350L

Molarity = 3.4 M

Using Molarity = n/V

3.4 = n/0.350

n = 3.4 × 0.350

n = 1.19mol

Using the formula below to calculate the mass of HCl;

mole = mass/molar mass

Molar mass of HCl = 1 + 35.5 = 36.5g/mol

mole = mass/MM

mass = 1.19 mol × 36.5g/mol

mass = 43.44g of HCl

2) At STP, HCl has a pressure of 1atm, a temperature of 273K

V = ?

n = 1.19 mol

R = 0.0821 Latm/molK

Using PV = nRT

V = nRT/P

V = 1.19 × 0.0821 × 273/1

Volume = 26.67L

Answer:

lead causes vessels to constrict, limiting the space for blood to flow (compare the size of the red circles.) This narrowing increases blood pressure, forcing the heart to work harder.

Answer:

By mimicking calcium and increasing cell stress, lead causes vessels to constrict, limiting the space for blood to flow. This forces the heart to work harder because the narrowing increases blood pressure.

Answer:

the third one...........

Answer:

wax melting off a candle

2NaOH(aq) + H2SO4(aq) => Na2SO4(s) + 2H2O(l)

This is a neutralization reaction.

Answer:

9

Explanation:

pH = -log[H+] = -log(1x10^9) = 9

Answer:

The products from the neutralization reaction are barium nitrate and water.  

The balanced chemical equation is

2 [tex]HNO_{3}[/tex] +  1 [tex]Ba(OH)_{2}[/tex]  -->  1 [tex]Ba(NO_3)_{2}[/tex] +  2 [tex]H_{2}O[/tex].  

Answer:

jk

Explanation:

Answer:

D. The pressure of the gas decreases!

Explanation:

According to Boyle's Law, there is an inverse relationship between the volume of a gas and its pressure!

So, if the volume of a gas increases, its pressure will decrease; the same thing will happen if the pressure of the gas increases -- the volume will decrease!

↑P↓V and ↓P↑V    <---- this is what it would look like visually!!

Hope this helps! :)

When the volume of a gas increases then the pressure of the gas decreases.

Ideal gas equation is a hypothesis which tells about the behavior of gas in different conditions and it will be represented as:
PV = nRT

From this equation it is clear that pressure and volume are inversely proportional to each other:
P ∝ 1/V

Means if pressure increases ten volume decreases or if pressure decreases then volume increases.

Hence option (4) is correct.

To know about ideal gas equation, visit the below link:
https://brainly.com/question/25290815

Answer:

c. 0.37 moles

Explanation:

To find the number of moles (n) in a certain number of atoms of a substance, we divide the number of atoms by Avogadro number (nA), which is 6.02 × 10²³ atoms.

That is,

n = number of atoms ÷ 6.02 × 10²³

According to this question, there are 2.25 x 10²³ atoms of carbon (C). The number of moles contained in this carbon is as follows:

n = 2.25 x 10²³ ÷ 6.02 × 10²³

n = 2.25/6.02 × 10 (23 - 23)

n = 0.374 × 1

n = 0.374moles

Answer:

D- They use the exchange rate to convert one's Country's currency to another's

Explanation:

Answer:

The air that is inside a ship is much less dense than water. That's what keeps it floating

Answer:

the anwer is glycolysis

Answer:

The correct option is 2.

Explanation:

In a nuclear reaction balanced we have that:

1. The sum of the mass number (A) of the reactants (r) is equal to the sum of the mass number of the products (p) [tex] \Sigma A_{r} = \Sigma A_{p} [/tex]

2. The sum of the atomic number (Z) of the reactants is also equal to the sum of the atomic number of the products [tex]\Sigma Z_{r} = \Sigma A_{p}[/tex]      

So, let's evaluate each option.

1) [tex]^{23}_{11}Na \rightarrow ^{24}_{11}Mg + ^{1}_{1}H[/tex]

The mass number of the reactant is:

[tex]A_{r} = 23 [/tex]

The sum of the mass number of the products is:

[tex] A_{p} = 24 + 1 = 25 [/tex]

This is not the correct option because it does not meet the first condition ([tex] \Sigma A_{r} = \Sigma A_{p}[/tex]).

2) [tex]^{24}_{11}Na \rightarrow ^{24}_{12}Mg + ^{0}_{-1}e[/tex]  

The mass number of the reactant and the products is:

[tex]A_{r} = 24 [/tex]

[tex] A_{p} = 24 + 0 = 24 [/tex]

Now, the atomic number of the reactants and the products are:

[tex]Z_{r} = 11 [/tex]

[tex] Z_{p} = 12 + (-1) = 11 [/tex]      

This nuclear reaction is balanced since it does meet the two conditions for a balanced nuclear equation, ([tex] \Sigma A_{r} = \Sigma A_{p}[/tex] and [tex] \Sigma Z_{r} = \Sigma Z_{p}[/tex]).  

3) [tex]^{24}_{13}Al \rightarrow ^{24}_{12}Mg + ^{0}_{-1}e[/tex]      

The mass number of the reactant and the products is:

[tex]A_{r} = 24 [/tex]

[tex] A_{p} = 24 + 0 = 24 [/tex]

Now, the atomic number of the reactants and the products are:

[tex]Z_{r} = 13 [/tex]

[tex] Z_{p} = 12 + (-1) = 11 [/tex]      

This reaction does not meet the second condition ([tex] \Sigma Z_{r} = \Sigma Z_{p}[/tex]) so this is not a balanced nuclear equation.

4) [tex]^{23}_{12}Mg \rightarrow ^{24}_{12}Mg + ^{1}_{0}n[/tex]

The mass number of the reactant and the products is:

[tex]A_{r} = 23 [/tex]

[tex] A_{p} = 24 + 1 = 25 [/tex]  

This reaction is not a balanced nuclear equation since it does not meet the first condition ([tex] \Sigma A_{r} = \Sigma A_{p}[/tex]).

Therefore, the correct option is 2.

I hope it helps you!

Answer:

The answer is SiO2

Explanation:

Because nonmetals are those who gain electrons and form ve ions