What is Darwin's name for species that do not appear to have changed for millions of years?

Answer:

2

Explanation:

because first shell ( k shell ) needs only 2 electron to complete its octet .

hope it helps

Answer:

False

Explanation:

Answer:  Approximately [tex]0.267 \frac{\text{J}}{\text{g}^{\circ}\text{C}}[/tex]

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Work Shown:

We have the following variables

note: the symbol [tex]\Delta[/tex] is the uppercase Greek letter delta. It represents the difference or change in a value.

Apply those values into the formula below. Solve for c.

[tex]Q = m*c*\Delta t\\\\714 = 52*c*51.5\\\\714 = 52*51.5*c\\\\714 = 2678*c\\\\2678*c = 714\\\\c = \frac{714}{2678}\\\\c \approx 0.26661687826737\\\\c \approx 0.267\\\\[/tex]

The specific heat of the unknown metal is roughly [tex]0.267 \frac{\text{J}}{\text{g}^{\circ}\text{C}}[/tex]

Answer:

In order from fastest to slowest, Steam > Liquid Water > Ice

Explanation:

As temperatures rise, particles are allowed to move faster and more freely. If you think about the phases of matter, the more compact something is (solids), the less the particles are able to move. Taking the temperate of ice into consideration, the cold further restricts fast movement of particles, whereas gas (especially steam in this case), in hot temperatures, is able to move quickly and freely in the atmosphere.

Answer:

Physical and chemical changes can occur almost everywhere, even in our bodies! Food must be broken down into a form that our cells can use. When we eat, our bodies physically break down food into small pieces. Our bodies also chemically break down those small pieces of food into tiny organic molecules.

Explanation:

Answer:

Environmental factors such as diet, temperature, oxygen levels, humidity, light cycles

And the presence of mutagens can all impact which of an animal's genes are expressed, which ultimately affects the animal's phenotype.

Answer:

Fluorine

Explanation:

These particles stick in the atoms and make them radioactive.

Answer:

group 15 ( the nitogen group)

Explanation:

Answer:

120.37 g/mol is the molar mass of magnesium sulfate

Answer:

0.0344 moles and 1.93g.

Explanation:

Molarity is defined as the ratio between moles of a solute (In this case, KOH), and the volume. With molarity and volume we can solve the moles of solute. With moles of solute we can find mass of the solute as follows:

Moles KOH:

15.2mL = 0.0152L * (2.26mol / L) = 0.0344moles

Mass KOH:

0.0344 moles * (56.11g/mol) = 1.93g of KOH

Answer:

B

Explanation:

The Niels Bohr's atomic model superior to all the earlier models is because it showed how the electron could orbit the nucleus without falling into it

Mercury(II) oxide, a red solid, decomposes when heated to produce mercury and oxygen gas. Mercury(II) oxide is a red solid. When it is heated, it decomposes into mercury metal and oxygen gas. A reaction is also considered to be a decomposition reaction even when one or more of the products are still compounds.

Answer:

Yes

Explanation:

A molecule has a center of symmetry when, for any atom in the molecule, an identical atom exists diametrically opposite this center an equal distance from it(Wikipedia).

A center of symmetry is said to exist in a molecule when reflection of all parts of the molecule through the center of symmetry produces an indistinguishable configuration(Housecroeft and Sharpe,2012)

Obviously, the Cl2 molecule has a center of symmetry, hence it is symmetrical. Reflection of the molecules through its center of symmetry produces an indistinguishable configuration.

Answer:

a. 0.528 M .

Explanation:

Hello!

In this case, since the given by-mass percent can be written as:

[tex]\frac{10gCdSO_4}{100g\ sol}[/tex]

By using the density and molar mass of the solute, cadmium sulfate, we can compute the molarity, by also making sure we convert from mL to L of solution:

[tex]M=\frac{10gCdSO_4}{100g\ sol}*\frac{1molCdSO_4}{208.46gCdSO_4} *\frac{1.10g\ sol}{1mL\ sol}*\frac{1000mL}{1L} \\\\ M=0.528M[/tex]

Thereby, the answer is a. 0.528 M .

Best regards.

The molarity of the solution of 10% by mass cadmium sulfate [tex](CdSO_4)[/tex] is approximately 0.479 M. The correct option is C.

To calculate molarity we need to find out how many moles of CdSO4 are present in the solution.

Given:

We need to calculate the mass of [tex]CdSO_4[/tex]:

Mass of [tex]CdSO_4[/tex] = (10% / 100%) * Total mass of the solution

Mass of [tex]CdSO_4[/tex] = (10 / 100) * 1000 g (since the volume is 1 L, and the density is 1.10 g/mL)

Mass of [tex]CdSO_4[/tex] =  100 g

So, the number of moles of CdSO4:

Number of moles of [tex]CdSO_4[/tex] = Mass of CdSO4 / Molar mass of CdSO4

Number of moles of [tex]CdSO_4[/tex] = 100 g / 208.46 g/mol

Number of moles of [tex]CdSO_4[/tex] ≈ 0.479 moles

Then, we calculate the molarity of the solution:

Molarity = Number of moles of CdSO4 / Volume of the solution (in liters)

Molarity = 0.479 moles / 1 L

Molarity ≈ 0.479 M

Hence, the molarity of the solution of 10% by mass cadmium sulfate [tex](CdSO_4)[/tex] is approximately 0.479 M. The correct option is C.

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Answer:

C₃H₈O₃

Explanation:

Let's assume we have 100 g of said compound. Then we would have:

Now we convert those masses into moles, using their respective atomic weights:

Then we divide those moles by the smallest number among them:

Finally we multiply those numbers by 3, so as to convert the 2.68 of H into an integer:

Thus the empirical formula is C₃H₈O₃

Answer: $6,600[tex]\alpha \sqrt[n]{x} \lim_{n \to \infty} a_n[/tex]

Explanation:

Answer:

B. Indicator

Explanation:

An indicator is used to determine whether an acid or alkali has been added to a solution.

An acid or alkali changes the hydrogen ion concentration in solution. This is indicated by the pH of the solution after which the acid or alkali has been added.

Answer:

529g/L

Explanation:

The concentration in chemistry is defined as the amount of solute in a determined amount of solution. The concentration in g/L means the amount of grams of solute (In this case, barium acetate), per liter of solution.

To solve this problem we need to find grams of solute (52.9g, already given) and the volume in liters (Converting 100mL to liters):

Volume:

100mL * (1L / 1000mL) = 0.100L

And concentration in g/L is:

52.9g / 0.100L =

Answer:

D.organism

Explanation:

A fungus from the kingdom fungi is an organism

Answer:

D. organism

......................

Answer:

[tex]c=0.2\ J/g^{\circ} C[/tex]

Explanation:

Given that,

Mass of a glass, m = 4 g

Initial temperature, [tex]T_i=5^{\circ} C[/tex]

Final temperature, [tex]T_f=45^{\circ} C[/tex]

Heat absorbed, Q = 32 J

We need to find the specific heat of the glass. The formula for the heat absorbed is given by :

[tex]Q=mc\Delta T\\\\c=\dfrac{Q}{m\Delta T}\\\\c=\dfrac{32\ J}{4\ g\times (45-5)^{\circ} C}\\\\=0.2\ J/g^{\circ} C[/tex]

So, the required specific heat of the glass is [tex]0.2\ J/g^{\circ} C[/tex].

Answer:Avogadro's number 6.02 x 10^23 of O2 molecules has a mass of 32 gm (atomic weight of O = 16 gm, 2 x 16 = 32).

Explanation:pls brainless

Answer:

11.2g of the 45% pure silver and 2.8g of the 50% pure silver.

Explanation:

14g of 46% pure silver contains:

14g*46% = 6.44g of silver are required. Thus, we can write:

6.44 = X*50% + Y*45% (1)

Where X is the mass of 50% pure silver and Y the mass of 45% pure silver.

As the mass of the sample must be 14g:

14g = X + Y (2)

Replacing (2) in (1):

6.44 = (14-Y)*50% + Y*45%

6.44 = 7 - 0.5Y + 0.45Y

-0.56 = -0.05Y

Y = 11.2g of the 45% pure silver

And:

14g-11.2g = X

X =

2.8g of the 50% pure silver

The required amount to obtain 14g of 46% pure silver is 2.8g of 50% silver and 11.2g of 45% silver.

To solve this question, we can assume it's a mathematical problem more than a chemistry problem.

let x represent the amount of 45% of pure Ag

let y represent the amount of 50% of pure Ag

But from the question, we only need 14g from both x and y

We can write an equation to represent this

[tex]x+y=14...equation(i)[/tex]

likewise, we can say that

[tex]0.45x+0.50y=14*0.46\\0.45x+0.50y=6.44...equation(ii)[/tex]

Solving both equations simultaneously,

[tex]x+y=14...equation(i)\\0.45x+0.5y=6.44...equation(ii)[/tex]

from equation (i)

[tex]x+y=14\\x=14-y...equation(iii)[/tex]

substitute equation (iii) into equation (ii)

[tex]0.45x+0.5y=6.44\\x=14-y\\0.45(14-y)+0.5y=6.44\\6.3-0.45y+0.5y=6.44\\[/tex]

collect like terms

[tex]-0.45y+0.50y=6.44-6.3\\0.05y=0.14\\y=\frac{0.14}{0.05}\\y=2.8[/tex]

Now we know the value of the 50% Ag which is 2.8g. Let's substitute it's value into equation (i) and solve for x

[tex]x+y=14\\x+2.8=14\\x=14-2.8\\x=11.2g[/tex]

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Answer:

im pretty sure its the last one

Explanation:

if plants dont have sun light they will die because the sunlight gives them the nutrients to survive

Answer:

17 mc/L

Explanation:

We habe heat that is taken by the ice for it to melt to be equal to the heat given by water.

ML = mc(290K - 273K)

ML = mc 17

Then we divide through by L

M = 17 mc/L

Please note that 273k as we have used in thIs solution is the temperature at which we can have water to freeze

Therefore the minimum mass of required ice = 17 mc/L

Answer:

Gallium

Explanation:

Answer:

Gallium

Explanation:

Answer:

This description can be expressed as follows:

Y > W > XY>W>X

And,

W=ZW=Z

From these expressions we are able to find out that the saltiest cell description is Y, while the less salty is X.

Now, salt is well known as a dehydrating agent. In a process called osmosis cells placed in a salty liquid environment lose water, how?

Well, cells have a semipermeable membrane, in which some substances can get inside. Cells also have water inside. If a cell is placed in a quite salty liquid environment, salt will make the water inside the cells to come out, drying the cell and diminishing its size.

So, in this case, according to the expressions above, Cell Y will look the smallest, while cell X will look the biggest.

If we pour pure water in each liquid, the salt concentration will change and each cell will begin to grow bigger, but the saltiest cell will still be smaller than the others with less salt concentration.

Answer:

Explanation:

From the combustion of carbon, the reactions occurring in limited oxygen conditions are:

[tex]C(graphite) + \dfrac{1}{2}O_{2(g)} \to CO_{(g)}[/tex]  

[tex]C(graphite) + O_{2(g)} \to CO_{2(g)}[/tex]  

If it occurs in excess, then any leftover CO changes to CO2. i.e.

[tex]C(graphite) + O_{2(g)} \to CO_{2(g)}[/tex]   ---- (1)

[tex]CO_{(g)} + \dfrac{1}{2}O_{(g)} \to CO_{2(g)}[/tex]          ----- (2)

From (1), the enthalpy change is:

[tex]\Delta H_{rxn1} = \Delta H^0_{fCO_2(g)} - ( \Delta H^0_{f C(graphite)}+ \Delta H^0_{fCO_2(g)}[/tex]

[tex]\Delta H_{rxn1} =-393.5 \ kJ/mol -(0+0)[/tex]

[tex]\Delta H_{rxn1} =-393.5 \ kJ/mol[/tex]

From (2), the enthalpy change is:

[tex]\Delta_{rxn2} = \Delta H^0_{fCO_2(g)} - ( \Delta H^0_{fCO(g)} + \dfrac{1}{2} \Delta H^0_{fO_2(g)})[/tex]

[tex]\Delta_{rxn2} = -393.5 \ kJ/mol -(-110.5 + \dfrac{1}{2}(0))[/tex]

[tex]\Delta_{rxn2} = -283.0 \ kJ/mol[/tex]

Subtracting (2) from (1), we get:

[tex]C(graphite) + O_{2(g)} \to CO_{2(g)} \ \ \ \Delta H_{rxn} = -393.5 \ kJ/mol}[/tex]

[tex]CO_{(g)} + \dfrac{1}{2} O_2(g) \to CO_{2(g)}} \ \ \ \Delta H _{rxn2} = -283.0 \ kJ/mol[/tex]

[tex]C(graphite) + O_{2(g)} \to CO (g) + \dfrac{1}{2}O_{2(g)} \ \ \ \Delta H_{rxn} = -110.5 \ kJ/mol[/tex]

[tex]C(graphite) + \dfrac{1}{2} O_{2(g)} \to CO (g) \ \ \ \Delta H_{rxn} = -110.5 \ kJ/mol[/tex]

The enthalpy change ΔH of the reaction = -110.5 kJ/mol

Answer:

From top to bottom of the periodic table ions will increase in radii. However, now left to right the radius is more of a function of the number of electrons. ... Similarly, O2- will be larger than F- as both have 10 electrons but Z=8 for oxygen and Z=9 for fluorine.

The oxygen ion is bigger than the fluorine ion , the reason is explained below

What is an Atomic Structure ?

An atom is composed of electrons , protons and neutrons .

Electrons have negative charge and are grouped in different shells around the nucleus

Protons and neutrons are present in positively charged nucleus

The nucleus has the most mass .The atomic number is the number of protons which is equal to the number of electrons.

Both oxygen atom and fluorine atoms are isoelectronic , they have 10 electrons in the shell , but oxygen has 8 protons while fluorine have 9 protons in the nucleus.

It is believed that as the atomic number increases so the attraction forces of the nuclei increases , making the nucleus smaller and the overall atom smaller

while the oxygen atom on reduction forms oxide anion , which is a dianion and a fluorine atom forms fluoride ion which has a single negative charge and the ion which has more electrons have more electron electron repulsion and the size of the ion is bigger.

Hence the oxygen ion is bigger than the fluorine ion.

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