Which of the following is a problem caused by dams?
O A. They can be used to generate electricity.
B. They provide water for the irrigation of crops.
.
O C. They impede fish migration and spawning.
O D. They collect and store water for human use.

Answer:

11.1mL

Explanation:

The reaction expression is given as:

          C₂H₅OH   + 3O₂ → 2CO₂ +  3H₂O

Given parameters:

density of ethanol  = 0.789g/mL

mass of CO₂ = 25g

Unknown:

Volume of ethanol = ?

Solution:

First find the number of moles of the CO₂ from the given mass;

 Number of moles  = [tex]\frac{mass}{molar mass}[/tex]

 Molar mass of CO₂ = 12 + 2(16) = 44g/mol

Number of moles  = [tex]\frac{25}{44}[/tex]    = 0.57mol

Then;

 Find the number of moles of ethanol used;

     3 moles of CO₂ is produced from 1 mole of ethanol;

    0.57mole of CO₂ will be produced from [tex]\frac{0.57}{3}[/tex]  = 0.19mole of ethanol

Now;

Find the mass of the ethanol from the given mole;

     Mass of ethanol  = number of moles x molar mass

     Molar mass of ethanol  = 2(12) + 5(1) + 16 + 1 = 46g/mol

      Mass of ethanol  = 0.19 x 46 = 8.74g

Then;

  Density is the mass per unit volume of a substance;

       Density  = [tex]\frac{mass}{volume}[/tex]

        Volume  = [tex]\frac{mass}{density}[/tex]  

          Volume  = [tex]\frac{8.74}{0.789}[/tex]   = 11.1mL

Answer:

The medical philosophy of the ancient Greeks in which the state of health and disease was determined by the four body “humours”—blood, yellow and black bile, and phlegm—and their relationships with the four elemental humours—air, fire, earth and water. Segen's Medical Dictionary.

Explanation:

Answer:

Mechanical

Explanation:

chemical

Explanation:

I took test 2020

1) He was born on February 8, 1834

2) He was born in Tobolsk, Russia

3) Mendeleev arranged the elements in order of increasing relative atomic mass.

4) Gallium, germanium, and scandium

5) He died on February 2, 1907

6) Protons (positive charge) and neutrons (neutral charge)

1. gaseous

2. Carbon Dioxide

Answer:

A. fluorine, 1.79 moles

Explanation:

Given parameters:

Mass of carbon  = 87.7g

Mass of fluorine gas  = 136g

Unknown:

The limiting reactant and the maximum amount of moles of carbon tetrafluoride that can be produced  = ?

Solution:

   Equation of the reaction:

             C    +   2F₂ →   CF₄  

let us find the number of the moles the given species;

  Number of moles = [tex]\frac{mass}{molar mass}[/tex]  

  C;   molar mass = 12;

            Number of moles  = [tex]\frac{87.7}{12}[/tex]   = 7.31moles

 F;  molar mass  = 2(19)  = 38g/mol

             Number of moles  = [tex]\frac{136}{38}[/tex]   = 3.58moles

 So;

   From the give reaction:

          1 mole of C requires 2 moles of F₂

         7.31 moles of C will then require 2 x 7.31 moles of F₂ = 14.62moles

But we have 3.58 moles of the F₂;

  Therefore, the reactant in short supply is F₂ and it is the limiting reactant;

 So;

       2 moles of F₂ will produce  mole of CF₄  

       3.58 moles of F₂ will then produce [tex]\frac{3.58}{2}[/tex]  = 1.79moles of CF₄

Answer:

option is (b)

Explanation:

please mark me as brilliant

Answer: D) Matter becomes more dense as it moves from gas to solid state

A gas expands to fill up the container of whatever shape or size. As it cools to a solid, the molecules get closer together and don't move as much (the molecules still will vibrate and move somewhat even in solid form). So effectively the volume of the object shrinks while the amount of mass stays the same. This is why the density increases when going from gas to solid.

Answer:

2

Explanation:

BIonary bi means 2

i hope this helps :)

Answer:

The electronegativity differences between carbon and oxygen are not very large.

Explanation:

Between the atoms of carbon monoxide exists a covalent bond which attaches the carbon to the oxygen.

In this type of bonding, both atoms shares a given number of valence electrons to attain chemical stability.

A substance is polar when there is a distinct charge separation between the species.

For covalent bonds, the electronegativity difference plays in important role in determining the polarity of the compound. When the difference is large, the compound will be polar but when the difference is very small or zero, no polarity will exist.

In between carbon and oxygen of carbon monoxide, the electronegativity difference is very low.

Answer:

Living Things Maintain Stable Internal Conditions When any living organism gets thrown off balance, its body or cells help it return to normal. In other words, living organisms have the ability to keep a stable internal environment. Maintaining a balance inside the body or cells of organisms is known as homeostasis.

Explanation:

Answer:

4 moles

Explanation:

The equation is 3H2 + N2 → 2NH3

so the ratio of moles would be

2:3 or 2/3

so 6*2/3 which is 4

hope this helped.

Answer:

4moles

Explanation:

Given parameters:

Number of moles of H₂ used  = 6moles

   Equation of the reaction:

           N₂  + 3H₂  →   2NH₃

       3 mole of H₂  was used to produce 2 mole of NH₃;

       6 mole of H₂ will produce [tex]\frac{6x2}{3}[/tex]   = 4 moles of NH₃

The number of moles of NH₃ produced is 4moles

Answer:

ON

Explanation:

Frictional force is a force that opposes the motion of body. It is because of friction that motion can be controlled and even walking is made possible.

Now, on a frictionless surface, there is no opposition to motion. Therefore, to keep the body moving there is no force required.

Answer:

Conduction

Explanation:

Answer:

Conduction is correct

Explanation:

Answer:

It is an Anion because there are more electrons than protons making it negative

Answer:

Correct

Explanation:

Balanced forces are always zero!

Answer:

Balanced

Zero

Explanation:

Answer:

Cell Differentiation and Tissue.

Explanation:

tissues are organized communities of cells that work together to carry out a specific function.

a. The unit cell is the smallest group of atom which have overall symmetry of a crystal, and from which is the entire letters can be buled built up by repetition in 3 dimensions.

b. The volume(v) of the unit cell is equal to the cell edge length (a)cubed.

c. density of polonium is 9.32g/cm3.

Answer:

Neutral atoms can be turned into positively charged ions by removing one or more electrons.

Explanation:

If there is an atom that has 9 protons and 9 electrons, removing an electron from the atom will gain a postive charge.

The phosphate group of one nucleotide bonds covalently with the sugar molecule of the next nucleotide, and so on, forming a long polymer of nucleotide monomers. The sugar–phosphate groups line up in a “backbone” for each single strand of DNA, and the nucleotide bases stick out from this backbone. The carbon atoms of the five-carbon sugar are numbered clockwise from the oxygen as 1′, 2′, 3′, 4′, and 5′ (1′ is read as “one prime”). The phosphate group is attached to the 5′ carbon of one nucleotide and the 3′ carbon of the next nucleotide. In its natural state, each DNA molecule is actually composed of two single strands held together along their length with hydrogen bonds between the bases.

Answer:

Explanation:

The discovery that DNA is the prime genetic molecule, carrying all the hereditary information within chromosomes, immediately focused attention on its structure. It was hoped that knowledge

of the structure would reveal how DNA carries the genetic messages that are replicated when chromosomes divide to produce two identical copies of themselves. During the late 1940s and early 1950s, several research groups in the United States and in Europe engaged in serious efforts—both cooperative and rival—to understand how the atoms of DNA are linked together by covalent bonds and how the resulting molecules are arranged in three-dimensional space. Not surprisingly, there initially were fears that DNA might have very complicated and perhaps bizarre structures that differed radically from one gene to another. Great relief, if not general elation, was thus expressed when the fundamental DNA structure was found to be the double helix. It told us that all genes have roughly the same three-dimensional form and that the differences between two genes reside in the order and number of their four nucleotide building blocks along the complementary strands.

Now, some 50 years after the discovery of the double helix, this simple description of the genetic material remains true and has not had to be ap- preciably altered to accommodate new findings. Nevertheless, we have come to realize that the structure of DNA is not quite as uniform as was first thought. For example, the chromosome of some small viruses have single-stranded, not double-stranded, molecules. Moreover, the precise orientation of the base pairs varies slightly from base pair to base pair in a manner that is influenced by the local DNA sequence. Some DNA se- quences even permit the double helix to twist in the left-handed sense, as opposed to the right-handed sense originally formulated for DNA’s general structure. And while some DNA molecules are linear, others are circular. Still additional complexity comes from the supercoiling (further twisting) of the double helix, often around cores of DNA-binding proteins.

Likewise, we now realize that RNA, which at first glance appears to be very similar to DNA, has its own distinctive structural features. It is principally found as a single-stranded molecule. Yet by means of intra-strand base pairing, RNA exhibits extensive double-helical character and is capable of folding into a wealth of diverse tertiary structures. These structures are full of surprises, such as non-classical base pairs, base-backbone interactions, and knot-like configurations. Most remarkable of all, and of profound evolutionary significance, some RNA molecules are enzymes that carry out reactions that are at the core of information transfer from nucleic acid to protein.

Clearly, the structures of DNA and RNA are richer and more intricate than was at first appreciated. Indeed, there is no one generic structure for DNA and RNA. As we shall see in this chapter, there are in fact vari- ations on common themes of structure that arise from the unique physi- cal, chemical, and topological properties of the polynucleotide chain

Answer:

Kindly check the explanation.

Explanation:

NADH is oxidized anaerobic conditions by lactate dehydrogenase because in order to transform or change Pyruvate into Lactate it has to happen in an anaerobic condition that is where we hardly find oxygen(in the presence of no oxygen).

The chemical compound or say the enzyme known as lactate dehydrogenase gets its proton from NADH( in a REDOX type reaction). After getting the proton from NADH, it uses that to convert Pyruvate into Lactate.

NB: the conversion can also be done in aerobic condition but more ATP will be produced. With anaerobic condition, less ATO is produced and there is re-oxidation.

Answer:

C:Strontium

Explanation:

Answer:

The volume of a gas is directly proportional to its temperature. Avagadro's Law- Gives the relationship between volume and amount of gas in moles when pressure and temperature are held constant. If the amount of gas in a container is increased, the volume increases.

Answer:

Decreasing the pressure applied to the gas.

Explanation:

Ap3x

Answer:

D)Gas particles move rapidly and have space between them.

Explanation:

Matter exists in three states namely: solids, liquids and gases. The particles contained in these three states are different from one another. In the gaseous state, the particles are FAR APART from one another i.e. space exists and they move at a very fast rate in contrast to the particles of a liquid, which have less space and move slower.

This rapid movement of gas particles within a less restricted space accounts for the reason why gaseous substances DIFFUSE more quickly than liquids.

Answer:

Asteroids are made of rock, metals, and other elements. Some even contain water. Asteroids that are mostly stone sometimes are more likely to lose piles of rubble. Asteroids that are mostly iron are more rock-solid.

Explanation:

Answer:

asteriods are made of rocks.   asteroids that are mostly iron are more, well, rock-solid

Explanation: