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Which phrase describes how vestigial structures provide evidence that suggests a common ancestor and supports that life changes over time?

Question 3 options:

some animals exhibit similar structures, possibly due to a common ancestor


some animals exhibit similar stages of embryonic development


some animals exhibit structures that are no longer used for any purpose


some fossils exhibit similar biological proteins

Explanation:

this is you questions answered

Answer:

Divide by the molar mass to get moles

Explanation:

The number of energy levels of zirconium is 5, and I know this because it is located in family five. Families are the rows across on the periodic table. The family number is always equal to the number of energy levels.Zirconium: properties of free atoms. Zirconium atoms have 40 electrons and the shell structure is 2.8.

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Explanation:

Answer:

two negative charges is the answer of your question

hormone erythropoietin (EPO) is responsible for the production of red blood cells.

Answer:

2.71

Explanation:

Explanation:

having no strongly marked or positive characteristics or features.

Answer:

The particles need energy to overcome the attractions between them. As the liquid gets warmer more particles have sufficient energy to escape from the liquid. Eventually even particles in the middle of the liquid form bubbles of gas in the liquid.

Answer: 59.41

Explanation:

The final temperature of the system has been 130[tex]\rm ^\circ C[/tex].

Specific heat can be defined as the amount of heat required to raise the temperature of 1 g of substance by 1-degree celsius.

The amount of heat lost and the heat gained have been equal.

Heat = mass × specific heat × change in temperature

Thus,

mc[tex]\Delta[/tex]T = mc[tex]\Delta[/tex]T

50 g × (10 - x) = 120 × (x - 80)

500 - 50x = 120x - 9600

70x = 9100

x = 130

Thus, the final temperature of the system has been 130[tex]\rm ^\circ C[/tex].

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Answer:

1. A. 9 eggs

2. B. 5:3

3. C. Exactly 44 g

4. C. Mass and atoms only

5. D. 6.81 g of PH₃

6. C. 88.4%

7. B. O₂

8. D. 30.8 g CO₂

9. B.

10. B.

11. C. 99 g

12. D. mole ratio

13. C. Theoretical

14. A. 6.0 mol H₂O

15. D. 39.7 g CH₃OH

16. A. 650 g HgO

17. D. 8.8 mol H₂

18. B. 82.6%

Explanation:

1. The number of eggs it takes to make 1 cake = 3 eggs

The number of eggs it takes to make 3 × 1 = 3 cake = 3 × 3 = 9 eggs

Therefore, the correct option is;

A. 9 eggs

2. The given reaction is presented as follows;

C₃H₈(g) + 5O₂(g) → 3CO₂(g) + 4H₂O(l)

In the above reaction, we have;

Moles of , O₂, reacted = 5 moles

Moles of , CO₂, produced = 3 moles

The ratio of the of O₂ reacted to moles of CO₂ produced = 5 moles:3 moles

∴ The ratio of the of O₂ reacted to moles of CO₂ produced = 5:3

The correct option is;

B. 5:3

3. The reaction is presented as follows;

O₂ (g) + C(s) → CO₂ (g)

From the reaction, 1 mole (12 g) of carbon produces 1 mole of CO₂

The molar mass of CO₂ = The mass of 1 mole of CO₂ = 44.01 g/mol

Given that the reaction is completed, the mass of CO₂ produced = The mass of 1 mole of CO₂ ≈ 44 g

The correct option is;

C. Exactly 44 g

4. The given reaction is presented as follows;

N₂ + 3 F₂ → 2NF₃

The initial number of atom = 2 + 6 = 8

The final number of atom = 2 × 4   = 8

∴ The initial number of atom = The final number of atom

Therefore, the number of atoms is conserved;

The mass of the reactants ≈ 28 g/mol + 3 × 37.996806 g/mol ≈ 141.993612 g/mol ≈ 142 g/mol

The mass of the product ≈ 2 × 71 g.mol = 142 g/mol

∴ The mass is conserved

Moles of reactants = 1 + 3 = 4

Moles of products = 2

∴ The number of moles is not conserved

The correct option is

C. Mass and atoms only

5. The molar mass of P₄ = 123.895048 g/mol

One mole of P₄ (123.895048 g) produces four moles (4 × 34.00) of PH₃

6.20 g of P₄. will produce (4 × 34.00)/(123.895048) × 6.20 g ≈ 6.80576 g ≈ 6.81 g

The correct option is D. 6.81 g of PH₃

6. The percentage yield = ((The actual yield)/(The ideal yield)) × 100

The actual yield of silver = 38.1 g

The ideal yield of silver = 43.1 g

∴ The percentage yield = ((38.1 g)/(43.1 g)) × 100 = 88.3990719258% ≈ 88.4%

The percentage yield = 88.4%

The correct option is C. 88.4%

7. The given chemical equation is presented as follows;

CS₂ (g) + 3 O₂ (g) → CO₂ (g) + 2 SO₂ (g)

The number of moles in 192 g of O₂ = 192 g/(32 g/mol) = 6 moles

Given that 3 moles of O₂ reacts with 1 mole of CS₂ to produce 1 mole of CO₂ and 2 moles SO₂,  therefore 2 × 3 = 6 moles of O₂ will reacts with 2 × 1 = 2 moles of CS₂ to produce 2 moles of CO₂ and 4 moles SO₂

∴ The limiting reactant is;

B. O₂

8. The given chemical equation is presented as follows;

2 C₈H₁₈ (g) + 25 O₂ (g) → 16 CO₂ (g) + 18 H₂O (l)

The number of moles in 10 g of C₈H₁₈, n₁ = (10 g)/(114.26 g/mol)

The number of moles of CO₂ produced, n₂ = (10 g)/(114.26 g/mol) × 16/2 ≈ 0.7 moles

The mass of CO₂ produced, m ≈ 44.01 × n₂ ≈ 44.01 g/mol × 0.7 moles ≈ 30.807 grams ≈ 30.8 grams

The theoretical yield of CO₂ from completely burning 10.0 g of C₈H₁₈ ≈ 30.8 grams of CO₂

The correct option is D. 30.8 g CO₂

9. The correct option is B. The limiting reactants determine the maximum amount of product that can be formed

10. Option B, which has 3 atoms of each element combining to form a product with 1 atom of one element and 2 atoms of the other element

The correct option is B.

11. By the conservation of mass, we have;

The mass of the reactants = The mass of the products

Let 'x' represent the mass of zinc in the products of the reaction

Therefore, we have;

61 g of calcium + 207 g of zinc chloride = 169 g of calcium chloride + x g of Zinc

∴  x g = 61 g + 207 g - 169 g = 99 g

The mass of zinc in the products of the reaction, x g = 99 g

The correct option is;

C. 99 g

12. The quantity that must be used to convert from one chemical substance to another is the mole ratio

The correct option is D. mole ratio

13. The maximum mass of the product that could form in a reaction is called the theoretical yield, which is option C.

The correct option is C. Theoretical

14. 1 mole of O₂ produces 2 moles of water (H₂O), therefore;

3 × 1 = 3.0 moles of O₂ will produce 3 × 2 = 6 moles of H₂O

The correct option is

A. 6.0 mol H₂O

15. 2 mole × 2.02 g/mol = 4.04 g of H₂ (g) produces 32.05 g CH₃OH (l)

∴ 5 g of H₂ (g) will produce 32.05 g × 5/4.04 ≈ 39.6658416 g ≈ 39.7 g of CH₃OH

The correct option is;

D. 39.7 g CH₃OH

16. 2 (2 × 216.59 g = 433.18 g) moles of HgO produces 1 mole of O₂

1.5 mole of O₂ will be produced by 1.5 × 2 = 3 moles (3 × 216.59 g = 649.77 g ≈ 650 g) of HgO

The correct option is A 650 g HgO

17. 3 moles of H₂ produces 2 moles of NH₃

The number of moles of NH₃ in 100 g of NH₃, n = 100 g/(17.04 g/mol) = 5.868544 moles

The number of moles of H₂ that will produce 5.868544 moles of NH₃ = 3/2 × 5.868544 moles = 8.802816 moles ≈ 8.8 moles

Therefore, the correct option is;

D. 8.8 mol H₂

18. The theoretical yield of PbO = (223.2/331.2) × 9.90 g = 6.67173913 g

The percentage yield = (5.51 g)/(6.67173913 g) × 100 ≈ 82.6%

The correct option is option B 82.6%.

Answer:

Thermal Energy: It refers to some distinct physical concepts, such as the internal energy of a system or heat or sensible heat. And these mode of transfer of heat include, convection, conduction and radiation which I have explained below.

Convection: This is a mode of transfer of heat in which bulk movement of molecules within fluids takes place, as these molecules move the heat obtained by each of the molecules will reach the new location.

Radiation: Radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium

Conduction: Conduction is the transfer of internal energy by microscopic collisions of particles and the movement of electrons within an object.

Answer:

15oC to K

oC +273

15+273

288K

Answer: Answer:

Explanation:

Apparent magnitude does not take into account the fact that not all stars are the same distance from Earth.

Apparent magnitude is only on a comparative scale that determines how bright a star looks from a theoretical distance of 32 light-years from Earth. Therefore, the correct option is option D.

Any large, gaseous celestial body that is capable of producing its own light and illuminates through radiation. Only a very small portion of the tens of milliards of milliards of stars that make up the observable cosmos are readily visible to the eye.

When measuring the brightness of a star, what is a limitation of using apparent magnitude rather than absolute brightness. Apparent magnitude is only on a comparative scale that determines how bright a star looks from a theoretical distance of 32 light-years from Earth.

Therefore, the correct option is option D.

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Answer and Explanation:

I believe −246.048 C or −411 F

K2SO4 + H2

Reason :Potassium is highly reactive

Answer:

K2SO4 + H2 this is the reaction.

Answer: The new pressure is 831 mm Hg

Explanation:

The combined gas equation is,

[tex]\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]

where,

[tex]P_1[/tex] = initial pressure of gas = 740 mm Hg

[tex]P_2[/tex] = final pressure of gas = ?

[tex]V_1[/tex] = initial volume of gas = 2.2 L

[tex]V_2[/tex] = final volume of gas = 2.0 L

[tex]T_1[/tex] = initial temperature of gas = 290 K

[tex]T_2[/tex] = final temperature of gas = 296 K

Now put all the given values in the above equation, we get:

[tex]\frac{740\times 2.2}{290}=\frac{P_2\times 2.0}{296}[/tex]

[tex]P_2=831mmHg[/tex]

The new pressure is 831 mm Hg

Answer:

Explained below.

Explanation:

Formula when magnesium reacts with hydrochloric acid is given by;

Mg(s) + 2HCl(aq) = MgCl2(aq) + H2(g)

So, from the equation, we can see that the gas formed is hydrogen.

This hydrogen gas is collected by a method known as water displacement.

This gas can be tested for by holding a burning splint near to the top of the test container. The resulting effect should be a high pitched pop sound because the hydrogen gas will react with the oxygen gas in the air to result in a small explosion.

Answer:

Area of rectangular poster = [tex]\frac{3}{16}[/tex] yard²

Explanation:

P.S - The exact question is -

Given - A rectangular poster is [tex]\frac{1}{4}[/tex] yard wide and [tex]\frac{3}{4}[/tex] yard tall.

To find - What is its area ?

Proof -

We know that ,

The area of rectangle = Length × Breadth

Here,

Given that,

Length of rectangle = [tex]\frac{3}{4}[/tex] yard

Breadth of rectangle = [tex]\frac{1}{4}[/tex] yard

∴ we get

Area of rectangular poster = [tex]\frac{3}{4}[/tex] × [tex]\frac{1}{4}[/tex]  yard²

                                          = [tex]\frac{3}{16}[/tex] yard²

⇒Area of rectangular poster = [tex]\frac{3}{16}[/tex] yard²

Answer:

Metals

Explanation:

It is a transition metal

The periodic table has a lot of different properties in how it is presented, one of these, is that the elements are separated in blocks by their properties.

From its position in the table, we can see that the correct option is d) metals.

The general way of knowing if an element is a metal or not, is to look if it is the D block in the periodic table.

This block contains all the transition metals (not all the metals) but every element in it is a metal. If we look for the mercury, we can see that it is in block D, just next to gold (Au).

Just from this, we can conclude that mercury is a metal, so the correct option is d.

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ANSWER

p2O5 is diphosphorus pentoxide.

Answer:

An atom of an element always contain three fundamental particles called electrons(e-) , neutron ( n zero) and protons ( p+)

An atom of an element always contains a proton, electron and neutron.

Every atom is made up of a nucleus and one or more electrons that are attached to the nucleus. One or more protons and a number of neutrons make up the nucleus. Only the most common type of hydrogen is neutron-free. Every solid, liquid, gas, and plasma is made up of atoms that are either neutral or ionized.

But when it comes to the word atom, we must go back to 400 B.C. Greece. And Democritus, a brilliant philosopher, proposed the Greek word atomos, which means uncuttable.

Every atom is made up of a nucleus and one or more electrons that are attached to the nucleus. One or more protons and a number of neutrons make up the nucleus.

Thus, An atom of an element always contains a proton, electron and neutron.

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Kitchen Math: Measuring

1. By understanding how to measure ingredients, time and temperature,

you take the guesswork out of cooking.

2. The two scales for temperature are Fahrenheit and Celsuis.

3. The three times to wash when cooking are: A. before cooking

B. during cooking

C. after handling of food

4. The three kinds of measurement are

A. estimated

B. ratio

C. calibrated measurement

5. Estimated measurement is great for foods such as soup.

6. Ratio cooking compares the amount of one ingredient to another

ingredient.

7. The most common kind of kitchen measurement in America is the English system.

8. One quart is almost a liter.

9. The metric system is based on tens.

Kitchen Math 3

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10. Measuring tools you find in almost every kitchen are timers, thermometers and measuring containers.

11. Water freezes at 32 Fahrenheit and 0° Celsius. Water boils at 212" Fahrenheit and 100° Celsius.

12. When measuring dry ingredients, you want to dip, scoop and scrape.

13. If your recipe calls for sifted flour, sift it before you measure.

14. Brown sugar, cooked rice and chopped parsley need to be packed down in measuring cups

15. When measuring liquids, get down at eye level.

16. Measuring spoons are used for both liquid and dry ingredients.

17. Use the back of a knife to scrape off dry ingredients when using a measuring spoon,

18. Taring is when you allow for the weight of a container or wrapper.

19. Dry ingredients do not weigh the same as wet ingredients.

20. A large egg weighs about 2 ounces.

21. Turn pancakes when you see bubbles on the top.

Answer:

Found in every living cell

Answer:

19.7 L N2

Explanation:

The volume of the nitrogen gas at STP is equal to 19.72 L.

The ideal gas equation can be defined as an equation that describes the behavior of an ideal gas. This equation gives by the product of the volume and pressure is equal to the product of the moles of gas, gas constant, and absolute temperature.

The mathematical form of the ideal gas law is given as follows:

PV = nRT

Where n is the moles, V is the volume, R is the universal gas constant and P is the pressure.

The temperature of the N₂ , T =  0° C = 273 K

The pressure of the gas at STP, P = 1 atm

The value of the universal gas constant, R = 0.082 atm L/K mol

The number of moles of N₂, n = 0.881 mol

Fill in the values n, R, P, and T in the equation, and we get:

1 × V = 0.881 × 0.082 × 273

V = 19.72 L

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Answer: 4.003 g/mol

Explanation:

So basically Molar mass is the atomic mass of an element and the atomic mass of Helium is 4.0026 or 4.003 g/mol