Plz Help I have One more time To retake and I can't fail it..​

Answer:

A. 36 percent recieved Bs

B. 40 percent of students received Cs

Explanation:

Amount of students: 12+18+20=50

Students with Bs: (18÷50) x 100 = 36%

Students with C's: (20÷50) x100 = 40%

On the first chemistry test 12 students got A, 18 students got B, and 20 student got C. Thus the percentage of students received B is 0.36 and percentage of students received c is 0.40

In mathematics, a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign %. A percentage is a dimension less unit and it has no unit.

In above question 12 student got A, 18 student got B, and 20 student got C.

So total number of student = 12 + 18 + 20 = 50.

Then the percentage of students received B is as follows:-

Percentage of students who got B = (student who got B/Total number of student) X 100.

=(18/50) X 100

= 36%

Now percentage of students who got C = (No of students who got C/Total students)X100

=(20/50) X 100

=40%.

Therefore,On the first chemistry test 12 students got A, 18 students got B, and 20 student got C. Thus the percentage of students received B is 0.36 and percentage of students received c is 0.40 percentage of students who got B is 36% and percentage of students who got C is 40%

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Answer:

1. 2.63x10^6

2. 39.2

Both answers have been rounded

Explanation:

an acid will give away a proton and become a conjugate base.

A base will accept a proton and become a conjugate acid.

Considering the definition of enthalpy of reaction, the correct answer is option C. a reaction with a negative enthalpy indicates that the reaction is exothermic.

The enthalpy of a chemical reaction as the heat absorbed or released when chemicals are transformed into a chemical reaction and it occurs at constant pressure.

The enthalpy is an extensive property, that is, it depends on the amount of matter present.

Finally, it must be taken into account that:

In summary, a reaction with a negative enthalpy indicates that the reaction is exothermic.

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Answer:

A and D are the answers

Explanation:

the other two don't make sense

The statements C and D are correct, i.e., curly hair have different protein structure from straight hair and curly hair results from a change in the gene.

Proteins are biomolecules made of amino acids. Proteins are very essential to all living things and contributes the body structure. Proteins are mainly up taken through diet and they are the main source of energy.

Hair is made of keratin protein. Keratin makes up our skin and nails too.Curly hair is originating by birth not developing over time. Curly hair is more likely to be occurring through inheritance.

The protein structure the hair follicle is some more bend for curly hair. Curly hair and straight hair originates from different gene traits. The gene type is inherited from the parents.

Hence, for people with curly hair have different protein structure and it result from a change in gene that code for hair structure. Thus options C and D are correct.

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Answer:

Metal

Element: Calcium

Valency: 2

Explanation:

To find the element, let's use the periodic table. (Look below)

We already went past 3 shells, just need the 2 electrons after it.

Just skip to the 4th row and count 2 to the right

We end up at Calcium.

Calcium is a metal and we're also on the alkaline earth metals column.

Calcium will need to lose 2 electrons to reach stability, so the valency is 2.

Answer:

if wrong sorry ok????

You're going to first balance the chemical equation.

After that, convert the grams of Na into moles of Na, and then multiply that with the ratio of moles of NaCl to Na, and then convert the mol of NaCl into grams in order to obtain the theoretical yield, since we are given that Na is the limiting reactant.

After that, plug the values into the yield formula, doing some basic algebra, and you should get your result.

You're going to first balance the chemical equation.

After that, convert the grams of Na into moles of Na, and then multiply that with the ratio of moles of NaCl to Na, and then convert the mol of NaCl into grams in order to obtain the theoretical yield, since we are given that Na is the limiting reactant.

After that, plug the values into the yield formula, doing some basic algebra, and you should get your result.

Answer:

The correct answer is - D.  the energy stored inside the center of an atom.

Explanation:

Each atom has a small center in it called the nucleus and the energy that holds the nucleus or center of the atom together in the atom is known as nuclear energy.

It is the energy that is stored in the center of the atom and normally does not come out, however, in some radioactive atoms the sends some part of the energy as radiation.

Thus, the correct answer is - D.  the energy stored inside the center of an atom.

Explanation:

Chemistry Teacher.

Chemical Engineer.

Forensic Scientist.

Geochemist.

Biochemists

Pharmacologist

Analytical Chemist

Envionmental chemist

Water Chemist

Catalysis

Answer:

For example, the bond between the sodium and chlorine atoms in sodium chloride (NaCl) is formed by the transfer of an electron from sodium to chlorine, creating Na + and Cl – ions. ... The electrostatic attraction between these ions provides the bonding in NaCl.

Answer:

formula for fermentation is: C6H12O6 → 2 C2H5OH + 2 CO.

Answer:

Age. ...

Residency. ...

Residence and Physical Presence.

Good Moral Character.

Attachment to the Constitution.

Language.

U.S. Government and History Knowledge.

Oath of Allegiance.

These are some requirements for obtaining citizenship .

Answer:

1 Anomalous Pairs. The rest of the  pairs of elements don't follow the follow Mendeleev's Principles . they are :

2Grouping of chemically dissimilar elements.  

3Position of Isotopes.  

4Electronic arrangement.  

5Separation of chemically similar elements.  

6The position of hydrogen.

Answer:

Movement of water from the area of high concentration of solute to the area of low concentration of solute.

Explanation:

Diffusion can be defined as the movement of gas molecules from a region of high concentration to a region of lower concentration until an equilibrium is attained or reached. This mixing of gas molecules in the liquid or gaseous state is due to their kinetic energy of random motion i.e without requiring bulk motion.

This ultimately implies that, diffusion is a phenomenon through which gas molecules in either a gaseous or liquid state spread out in response to a concentration gradient, which is simply the difference in concentration of the gases across a space.

During diffusion, molecules move from areas of high concentration to areas of low concentration. Also, diffusion does not require energy to move molecules.

Hence, the process of diffusion can be described as movement of water from the area of high concentration of solute to the area of low concentration of solute.

A solute can be defined as a substance that is typically dissolved in a liquid solvent such as water, coffee, tea, etc., to produce a solution.

Answer:

Measurement is defined as the act of measuring or the size of something. An example of measurement means the use of a ruler to determine the length of a piece of paper. ... Extent, quality, or size as determined by measuring; dimension. A waist measurement of 32 inches.

Explanation:

The comparison o unknown quantity with known standard quantity is called measurement.

Answer:

Analytical Chemist

Forensics

Toxicologist

Biochemist

Chemical Engineer

Laboratory Technician

Pharmacologist

Chemical Technician

Materials Scientist

Environmental Chemist

Answer:

b) it gets accumulated in the respiratory system which then halts or slows down the supply of oxygen to the brain hence leading to death

Answer:

A quantity having direction as well as magnitude is called vector.

Answer:

C A B

Explanation:

come on, you also know this from normal water waves.

which ones are stronger (= have more energy) ? the small ones or the big ones ?

and the same applies to all waves. the bigger the waves (higher amplitude), the more energy.

Answer:

single, double, and triple bonds

Answer:

it means air pollution Environment. The chemicals and nutrients found in fertilizers, while beneficial for agricultural crops, can be lethal in high doses for fish, birds and other wildlife. Pesticides, designed to kill pests chemically, are also dangerous when leached into soil or groundwater supplies.

Answer:

D.Something that can be observed or measured without changing the identity of the substance.

Sodium salt might not be prepared by double decomposition because the method is used in preparing insoluble salts.

Double decomposition method serves as the method that is used in preparing compounds which entails reaction between two soluble compounds and after reaction soluble and insoluble products are produced.

Therefore, since most of the sodium salt are soluble salt , Double decomposition cannot be used to prepare them.

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The first shell can only hold 2 electrons, but the pupil placed in 8 electrons.

The second shell can hold up to 8 electrons, but the pupil only placed in 2 electrons.

Flourine only has 9 total electrons, yet there are 10 electrons in the diagram.

Answer:

Explanation:

In the Fluorine atom there are 2 electrons in the innermost shell and 7 i the outer shell.

The final temperature of the water, T2 = 38.57°C

Temperature can be defined as a measure of the degree of hotness or coldness of a physical object (body). Thus, it is measured with a thermometer and its units are degree Celsius (°C), Fahrenheit (°F) and Kelvin (°K).

A calorie refers to the amount of heat required to raise the temperature of a gram of water by one (1) degree Celsius (1°C).

Given the following data:

The specific heat capacity of water is 4.2 J/g°C.

To find the final temperature of the water (T2):

Mathematically, the quantity of energy (heat capacity) is given by the formula;

[tex]Q = mcdt[/tex]

Where;

Substituting the values into the formula, we have;

[tex]420 = 3.5 \; * \; 4.2 \; * \; dt[/tex]

[tex]420 = 14.7 \; * \; dt\\\\dt = \frac{420}{14.7}[/tex]

Change in temperature, dt = 28.57°C

Next, we would solve for the final temperature by using this formula;

[tex]dt = T2 - T1[/tex]

[tex]28.57 = T_{2} - 10\\\\T_{2} = 28.57 \; + \; 10\\\\T_{2} = 38.57[/tex]

Final temperature, T2 = 38.57°C

Therefore, the final temperature of the water, T2 is equal to 38.57°C

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Answer:

The correct answer would be 3. The number of atoms of each element in the reactants equals the number of atoms of each element in the products.

Explanation:

The law of conservation of matter states that energy cannot be created or destroyed, only transfered. Thus, option 3 is correct.

The Sun radiates sunlight (visible)  photons

Photons from the Sun strike Earth and become infrared photons.

Earth radiates infrared photons into the atmosphere

CO2 in the atmosphere absorbs infrared  photons.

CO2 in the atmosphere emits infrared photons back toward Earth.

Certain gases are known to contribute towards global warming. Such gases are called greenhouse gases. The infrared rays from the sun are absorbed by these gases as they are re-emitted from the earth and re-emitted.

The sun radiates photons to the earth which is re-radiated into outerspace from the earth's surface. CO2 and other greenhouse gases absorbs these gases and re-emit them to the earth thereby causing a gradually rise in the temperature of the earth called global warming.

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Answer: 0.3 moles NH3

Explanation: