PLeas hurry

Which of the following matches a human action with its impact?

Construction of dam : Scarcity of water for animals

Use of fertilizers : Increase in the population of aquatic animals

Decrease in honeybee population : Increase in plant population

Construction of roads : Improvement in quality of water in local lakes

Answer:

atoms

Explanation:

Answer:650K

Explanation:

Answer: 650K (1.45/145 = 6.50/x)

Explanation:

Answer:

C) It is the reactant that is left over after the reaction stops.

Explanation:

The excess reactant is the reactant that is left over after the reaction stops. The extent of the reaction is not determined by this reactant.

A limiting reactant is a reactant that is in short supply within a given reaction.

Such reactants determines the extent of chemical reaction.

Answer: C) It is the reactant that is left over after the reaction stops.

Explanation:

Answer:

Cretaceous Period

Explanation:

Dinosaurs went extinct about 65 million years ago (at the end of the Cretaceous Period), after living on Earth for about 165 million years.

Answer:

C. NH₄Cl

Explanation:

The compound with the element ratio 1 : 4 : 1 from the given choices is NH₄Cl.

An element is a pure substance made up of distinct number of atoms. Elements are unique and are different from other elements because of the nature of their atoms.

We often delineate an element using chemical symbols.

   In the compound NH₄Cl;

There are 3 elements:

           Number of atoms

N                      1

H                      4

Cl                     1

Answer:

794.96 kilojoules

Explanation:

multiply 190 by 4.184

There are 0.798 kilojoules an individual must consume when he/she takes a snack that has 190 Calories.

One calorie may be defined as a unit for measuring heat wjhich is equivalent to the amount of heat required to increase the temperature of one gram of water one degree Celsius.

According to the question,

The amount of calories a snack contains = 190 calories

Now, you should be required to convert calories into Joules.

1 calorie ≅ 4.2 Joules.

190 calories = 190 × 4.2 = 798 Joules.

Now, according to the conversion factor, 1 kilojoule = 1000 joules

∴ 798 Joules = 798/1000 = 0.798 kilojoules.

Therefore, there are 0.798 kilojoules an individual must consume when he/she takes a snack that has 190 Calories.

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Answer:

A plant cell has a cell wall but an animal cell dosnt have one

Explanation:

Brainliest plz

Explanation:

the cell wall surrounds the plasma membrane of the plant and provides tensile strength and protection against mechanical

Answer:Al3+ indicates an ion of aluminum having a charge of + 3. I.e., since an aluminum atom normally has 13 protons and 13 electrons, this ion has 10 electrons (-10 charge) and 13 protons (+ 13 charge) giving it a charge of + 3 (-10 + 13 = +3).

Explanation:

The ion will have a charge of +3

The components of an atom and their charges are:

The charge of an ion will therefore depend on the number of electrons and protons as they cancel each other out.

The number of excess protons in this ion will be:

= Number of protons - number of electrons

= 13 - 10

= 3

Protons have a positive charge so there will be a charge of +3 as there are 3 excess protons.

In conclusion, this ion will have a charge of +3.

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Answer:

The new temperature will be 565.83 K.

Explanation:

Gay Lussac's law establishes the relationship between the temperature and the pressure of a gas when the volume is constant. This law says that the pressure of the gas is directly proportional to its temperature. This means that if the temperature increases, the pressure will increase; or if the temperature decreases, the pressure will decrease.

In other words, Gay-Lussac's law states that when a gas undergoes a constant volume transformation, the ratio of the pressure exerted by the gas temperature remains constant:

[tex]\frac{P}{T} =k[/tex]

When an ideal gas goes from a state 1 to a state 2, it is true:

[tex]\frac{P1}{T1} =\frac{P2}{T2}[/tex]

In this case:

Replacing:

[tex]\frac{180 kPa}{291 K} =\frac{350 kPa}{T2}[/tex]

Solving:

[tex]T2=350 kPa*\frac{291 K}{180 kPa}[/tex]

T2= 565.83 K

The new temperature will be 565.83 K.

Answer:

I think A and D and E

Explanation:

that is an example of mechanical wave

1. Double-Replacement reactions

2. Decomposition  

3. Combustion

4. Syntesis

5. Single replacement

Given

Chemical equations

Required

Type of reaction

Solution

1. 2AgNO₃ + MgCl₂ ⇒ 2AgCl + Mg(NO₃)₂

Double-Replacement reactions. Happens if there is an ion exchange between two ion compounds in the reactant

2. 2KBr⇒2K +Br₂

Decomposition  

Single compound breaks down in to 2 or more products

3. C₃H₈ + 5O₂ ⇒ 4H₂O + 3CO₂

Combustion

Hydrocarbon and Oxygen reaction and form water and carbon dioxide

4. NaO + H₂O ⇒ NaOH

Syntesis

2 or more reactants combine to form a single product

5. Zn + CuCl₂ ⇒ZnCl₂ + Cu

Single replacement

One element replaces another element from a compound

Answer:

Ratio of the change in length to original length.

Explanation:

(Δl)/l

HCl as a limiting reactant

volume of the gas(H₂)= 0.672 L

mass of salt : =2.67 g

mass of excess left :  4.86 g

Given

5.4 g Al

300 mL of 0.2 mol/L HCl

Required

limitng reactants

volume of the gas(H₂)

mass of salt

mass of excess left

Solution

Reaction

2Al + 6HCl → 2AlCl₃ + 3H₂

mol Al = 5.4 g : 27 g/mol = 0.2

mol HCl = 0.3 L x 0.2 mol/L = 0.06

mol : coefficient of reactants :

Al = 0.2 : 2 = 0.1

HCl = 0.06 : 6 = 0.01

HCl as a limiting reactant(smaller ratio)

Al as an excess reactant

mol H₂ = 3/6 x mol HCl = 3/6 x 0.06 = 0.03

volume (STP : 1 mol=22.4 L) :

= 0.03 x 22.4 L

= 0.672 L

mol AlCl₃ = 2/6 x mol HCl = 2/6 x 0.06 = 0.02

mass AlCl₃ :

= mol x MW

= 0.02 x 133.5

=2.67 g

mol (reacted) : 2/6 x mol HCl = 2/6 x 0.06 = 0.02

mol (unreacted) : 0.2 - 0.02 = 0.18

mass = 0.18 x 27 g/mol = 4.86 g

Answer: The molecular formula will be [tex]C_2H_4O_2[/tex]

Explanation:

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of C = 40.0 g

Mass of O = 53.3 g

Mass of H = 6.66 g

Step 1 : convert given masses into moles.

Moles of C =[tex]\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{40.0g}{12g/mole}=3.33moles[/tex]

Moles of O =[tex]\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{53.3g}{16g/mole}=3.33moles[/tex]

Moles of H =[tex]\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{6.66g}{1g/mole}=6.66moles[/tex]

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = [tex]\frac{3.33}{3.33}=1[/tex]

For O =[tex]\frac{3.33}{3.33}=1[/tex]

For H = [tex]\frac{6.66}{3.33}=2[/tex]

The ratio of C : O : H = 1: 1: 2

Hence the empirical formula is [tex]COH_2[/tex]

The empirical weight of [tex]COH_2[/tex] = 1(12)+1(16)+2(1)= 30g.

The molecular weight = 60 g/mole

Now we have to calculate the molecular formula.

[tex]n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{60}{30}=2[/tex]

The molecular formula will be=[tex]2\times CH_2O=C_2H_4O_2[/tex]

Answer:

a

Explanation:

Answer:

If im correct it’s radioisotope

Explanation:

Scientists often look at how much of isotopes of : Carbon-14  have decayed

To determine the age of fossils archeologist make use of the carbon-14 dating ( i.e. making use of naturally occurring radioisotope ¹⁴C ) which is used to determine the age of fossils or material that were once in living on earth.

Carbon has about three (3) isotopes ( Carbon-12, Carbon-13 and Carbon-14 ) .but Carbon-14 isotope is most useful in determining the age of fossils and once-living things

Hence we can conclude that scientists often look at how much of isotopes of Carbon-14 have decayed to help estimate the age of fossils.

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Answer:

Explanation:

The trick here is to realize that if you know the volume of a gas at STP, you can use the fact that

1

mole of any ideal gas occupies

22.7 L

under STP conditions to calculate how many moles of gas you have in your sample.

Under STP conditions:

1 mole of an ideal gas = 22.7 L

−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

In your case, you know that your sample of gas occupies

2.28 L

under STP conditions, which are currently defined as a pressure of

100 kPa

and a temperature of

0

∘

C

.

This means that your sample will contain

2.28

L

⋅

molar volume of a gas at STP



1 mole gas

22.7

L

=

0.10044 moles gas

Now, the molar mass of the gas is the mass of exactly

1

mole of the gas. In your case, you know that you get

3.78 g

for every

0.10044

moles, which means that you have

1

mole

⋅

3.78 g

0.10044

moles

=

37.6 g

Since this is the mass of

1

mole of gas, you can say that the molar mass of the gas is

molar mass = 37.6 g mol

−

1

−−−−−−−−−−−−−−−−−−−−−−−

Answer:

Sodium hydroxide is deliquescent (absorbs moisture from the atmosphere) solid. It cannot be weighed accurately. Therefore, it is not possible to prepare a standard solution of sodium hydroxide of accurately known concentration by weighing NaOH.

don't know sorry.........

Answer:

1.725e+18

Explanation:

Answer:

1 mole of zinc has 6.023 x 1023 atoms

So, 4.1 moles will have 4.1 x 6.023 x 1023 atoms = 24.694 x 1023 atoms

Explanation:

Answer:

photosynthesis  are ligt water and carbon dioxide

Explanation:

Plants make their own food out of inorganic compounds through a process called photosynthesis that takes place in the leaves. The ingredients necessary for photosynthesis are light, water and carbon dioxide.

Answer:

z3 xCo2 + 75 = s01 + h20 = Z2

Explanation:

The study of chemicals is called chemistry.

The correct answer is A.

A combination reaction is defined as the joining of two different elements to form a new compound is called a combination reaction. A new compound is always formed in the reaction.

According to the question, in option A the [tex]Li_2Co_3[/tex] is formed and in reaction 4 [tex]H_2So_4[/tex] is formed.

Hence, the correct option is A that is Z1 and Z4.

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Answer:

The pH indicates how acidic or basic a solution is.

Explanation:

i just took the test and got it right.

pH of a solution is the measure of how acidic or basic the solution is. It is determined based on the H+ ion concentration in the solution. Hence, option C is correct.

pH of a solution is the measure of the H+ ion concentration in a solution. It determines the acidity or basicity of the solution. Mathematically it is the negative logarithm of H+ ions concentration.

pH = - log [H+]

A pH scale can be used to determine the acidity or basicity of a solution. If the basicity is 7, then the solution is neutral. If the pH is less than 7 then the solution is acidic and a pH above 7 is basic solution.

Red- green color in pH scale represent the acidic solution where green is neutral and cyan to dark blue color is given by bases. Using a litmus paper the acidity can be checked based on these color change.

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Answer:

31g

Explanation:

80g(Ca)+m(H2O)=114g(CaOH)+2g(H2)

the total mass of the prodicts doesn't change throughout the process

80g+m(H20)=116g

m(H20)=31g

Answer:

C.)He is incorrect. Dissolving salt in water and evaporation of the water are both physical changes. The reappearance of salt is evidence that the change was reversible by a physical change, so it could not be a chemical change.

Explanation:

From the analogy of the problem presented, we can see that Henry is grossly incorrect. His conclusion from the process of the experiment he carried out is completely wrong.

Physical changes are changes that alters the physical properties of matter particularly the form and state.

Chemical changes leads to the formation of a new kind of matter.

 We can see that since the salt was obtained back after evaporation, no change has occurred to it.

Therefore, evaporation in itself is a physical change process.

Answer:

c on ed

Explanation:

Answer:

The new concentration of the solution is;

0.01 M

Explanation:

The question relates to concentration of solution and proportion of mixtures

The given parameters are;

The volume of water added to the 0.1 M solution = 900 mL

The initial volume of the solution to which water was added = 100 mL

Therefore, the total final volume of the solution = 100 mL + 900 mL = 1000 mL = 1 L

The concentration of the solution = 0.1 M

The number of moles present in the solution, 'n', is given as follows;

n = 100 mL/(1000 mL) × 0.1 M = 0.01 moles

Given that no more concentrated solution was added, we have;

The number of moles in the 100 mL solution   = The number of moles in the 1,000 mL solution

Therefore, the number of moles in the 1,000 mL (1 L) solution = 0.01 moles

Therefore;

The new concentration of the 1,000 mL (1 L) solution = 0.01 moles/(1,000 mL) = 0.01 moles/(1 L) = 0.01 M (By definition of the molarity of a solution)

The new concentration of the 1,000 mL (1 L) solution = 0.01 M.

D. 0.01 M

Given:

The volume of water added to the 0.1 M solution = 900 mL

The initial volume of the solution to which water was added = 100 mL

So,

The total final volume of the solution = 100 mL + 900 mL = 1000 mL = 1 L

The concentration of the solution = 0.1 M

Firstly we need to find the number of moles which is represented by 'n':

 [tex]n = \frac{100mL}{1000mL}* 0.1 M\\\\n = 0.01 \text{moles}[/tex]

 The number of moles in the 100 mL solution   = The number of moles in the 1,000 mL solution

Thus,

The number of moles in the 1,000 mL (1 L) solution = 0.01 moles  

For calculation of new concentration:

Using Molarity formula:

The new concentration of the 1,000 mL (1 L) solution [tex]= \frac{0.01\text{ moles}}{1000mL} = \frac{0.01\text{ moles}}{1L} = 0.01 M[/tex]

The new concentration of the 1,000 mL (1 L) solution = 0.01 M.

Thus, the correct option is D.

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Bungee jumpers that stand on a 200 ft building

Given

A building 100 ft tall

A building 200ft tall

Required

Which has the greatest potential energy

Solution

Potential energy is owned by an object because of its height

Can be formulated :

PE = m . g . h

g = acceleration due to gravity ,(m/s²)  

h = height , (m)  

m = mass, (kg)  

So PE is influenced by 3 factors:

the object's mass, its gravitational acceleration at that place and its height

Because the mass and gravitational acceleration are the same, the largest PE is owned by bungee jumpers that stand on a 200 ft building

Answer:

Filtration is the answer