Group one elements, such as lithium, sodium, and
potassium, are known as
OA) alkali metals.
B)
halogens.
C) alkaline earth metals.
D) noble gasses.

Answer:

Explanation:

Three temperature scales are currently in use. Their units are °F (degrees Fahrenheit), °C (degrees Celsius), and K (kelvin). The Fahrenheit scale, which is the most commonly used scale in the United States outside the laboratory, defines the normal freezing and boiling points of water to be exactly 32°F and 212°F, respectively.

The Celsius scale divides the range between the freezing point (0°C) and boiling point (100°C) of water into 100 degrees. The kelvin is the SI base unit of temperature: it is the absolute temperature scale. By absolute we mean that the zero on the Kelvin scale, denoted by 0 K, is the lowest temperature that can be attained theoretically. On the other hand, 0°F and 0°C are based on the behavior of an arbitrarily chosen substance, water.

The size of a degree on the Fahrenheit scale is only 100/180, or 5/9, of a degree on the Celsius scale. To convert degrees Fahrenheit to degrees Celsius, we write:

?ºC = (ºF - 32ºF) * 5ºC/9ºF

The following equation is used to convert degrees Celsius to degrees Fahrenheit:

?ºF = 9ºF/5ºC * (ºC) + 32 ºF

Both the Celsius and the Kelvin scales have units of equal magnitude; that is, one degree Celsius is equivalent to one kelvin. Experimental studies have shown that absolute zero on the Kelvin scale is equivalent to –273.15°C on the Celsius scale.

Thus, we can use the following equation to convert degrees Celsius to kelvin:

?K = (ºC +273.15ºC) * 1K/1ºC

Answer:

287.6g CHCl₃

Explanation:

We can determine the structure of Chloroform, dividing the mass of each element in its molar mass:

C = 12.0g * (1mol /12g) = 1 mol C

H = 1.01g * (1mol / 1.01g) = 1 mol H

Cl = 106.4g * (1mol / 35.45g) = 3 moles Cl

The structure is CHCl₃. And its molar mass is: 12.0g C +1.01g H + 106.4g Cl = 119.41g/mol

Now, the moles of carbon in the second sample = Moles of chloroform are:

28.9g C * (1mol / 12g) = 2.408 moles C = Moles CHCl₃

And its mass is:

2.408 moles CHCl₃ * (119.41g/mol) =

Answer:

Explanation:

All atoms (except for group 0 elements) of elements tend to achieve stability by having there outermost shell completely filled; achieving an octet configuration. During chemical bonding, atoms tend to achieve stability majorly in one of the two ways below

1) Ionic or electrovalent bonding: This involves the transfer of electrons from a positively charged ion (cation) to a negatively charged ion (anion). Here, no molecule is formed. For instance, in the formation of a sodium chloride (NaCl) salt. Sodium ion donates the single electron on it's outermost shell (to achieve it's octet configuration) to chloride ion (which needs just one more electron in it's outermost shell to achieve it's octet configuration).

Na⁺ + Cl⁻ ⇒ NaCl

2) Covalent bond: This involves the sharing of lone pair of electrons between two atoms to form a molecule. For example, the outermost shell of an oxygen atom, has two single electrons (that are not in pair), these single electrons can form covalent bond independently with hydrogen atoms (to form water) that also have just one electron in their shells. Hence, at every "covalent bonding site", an electron from oxygen and an electron of hydrogen is shared between the two atoms in order to achieve a stable configuration (Here, we have two "covalent bonding sites").

Answer:

[tex]1.09nL[/tex]

Explanation:

Hello,

In this case, given that 1 gal equals 4 qt, 1 qt equals 0.9464 L and 1 L equals 1x10⁹ nL, the dimensional analysis turns out:

[tex]2.87x10^{-10}gal*\frac{4qt}{1gal} *\frac{0.9464L}{1qt}*\frac{1x10^9nL}{1L}\\ \\1.09nL[/tex]

Best regards.

Answer:

C

Explanation:

just took the test

The pair of chemical elements which would most likely combine to form a salt is: Cs and I.

An inorganic substance can be defined as a substance that doesn't contain both carbon and hydrogen.

In Chemistry, some examples of an inorganic compound include the following:

A salt comprises an ionic assembly of both the negative ion (anion) of an acid and a positive ion (cation) of a base, which results in the formation of a neutral chemical compound.

Hence, cesium (Cs) which has a a positive charge of one (+1) and an iodine (I) ion with a negative charge of one (-1) would combine or react to form neutral cesium iodide (CsI).

In conclusion, a salt is most likely to be formed from the reaction of cesium (Cs) and iodine (I).

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Answer:

1600

Explanation:

5×10^4÷2.5×10^2

(5×10^4)

(10^4)

(5×40)

(200)

(200÷2.5)

(80)

(80×10^2)

(10^2)

(20)

(80×20)

Answer is 1600.

Sorry if it's not correct.

Answer:

0.000128 kilometers

Answer:

0.000128 kilometre..

Answer:

a

Explanation:

N2 means that each nitrogen atom is bonded to another and they act as a unit. 2N means that each nitrogen atom is separate from the other. So the correct options are B and D.

The chemical element nitrogen has an atomic number of seven (it has seven protons in its nucleus). Two nitrogen atoms are securely linked together to form the chemical molecule known as molecular nitrogen (N2). At normal temperatures and pressures, molecular nitrogen is a colorless, odorless, tasteless, and inert gas.

Nitrogen makes up around 78% of the Earth's atmosphere. Molecular nitrogen is a molecule that is practically inert due to the strong triple bond that connects its atoms. But when nitrogen bonds do break, the ensuing substances are frequently quite reactive.

Numerous different forms of contaminants include atoms of nitrogen. Nitric oxide (NO) and nitrogen dioxide can be produced during high-temperature combustion when nitrogen gas is present, such as in car engines (NO2). Both gases contribute to the creation of nitric acid, which is a component of acid rain, and peroxyacetyl nitrate (PAN), which is a key component of smog. They are both toxic on their own.

Therefore the correct options are B and D.

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Answer:

c. alcohol oxidation

Explanation:

The police often use a device called a breathalyzer to test drivers suspected of being drunk. The chemical basis of this device is a redox reaction. A sample of the driver’s breath is drawn into the breathalyzer, where it is treated with an acidic solution of potassium dichromate. The alcohol (ethanol) in the breath is  converted to acetic acid as shown in the following equation:

3 CH₃CH₂OH + 2 K₂Cr₂O₇ + 8H₂SO₄   → 3 CH₃COOH + 2 Cr₂(SO₄)₃ + 2 K₂SO₄ +1 11H₂O

ethanol + potassium dichromate (orange yellow)  + sulfuric acid → acetic acid +  chromium(III) sulfate (green) + potassium sulfate + water

In this reaction, the ethanol is oxidized to acetic acid and the chromium(VI) in the orange-yellow dichromate ion is reduced to the green chromium(III) ion. The driver's blood alcohol level can be determined readily by measuring the degree of this color change (read from a calibrated meter on the instrument).

Answer:

A-210, n-125

A-207, n-122

A-209, n-124

Explanation:

The mass number is the sum of the number of protons and neutrons in the nucleus of an atom.

Astatine has an atomic number of 85, this is the number of protons in its nucleus. We must subtract the given number of neutrons in each option from the mass number and consider the difference. If the difference between the mass number and number of neutrons is exactly 85, then that option represents one of the isotopes of astatine.

Answer:

See explanation

Explanation:

The shorthand nuclear reaction equations have been given; the first particle in the parentheses is a reactant particle while the second particle is a product particle. These can now be rewritten as the longhand equations as follows;

238/92U + 4/2 He -------> 241/94Pu + 1/0 n

238/92U + 4/2 He ------> 241/94Pu + 1/0 n

14/7N + 4/2 He------> 17/8O + 1/1 p

56/26Fe + 2 4/2 He----> 60/29Cu + 4/2 He

Answer:

A. No precipitate is formed

Explanation:

Hello,

In this case, since the reactions are:

[tex]Ca^{2+}(aq)+2HCl(aq)\rightarrow CaCl_2(aq)+2H^+(aq)\\\\Ba^{2+}(aq)+2HCl(aq)\rightarrow BaCl_2(aq)+2H^+(aq)[/tex]

We evidence no formation of insoluble salts or precipitates since both calcium and barium chlorides are largely soluble in water due to the ionic bond which binds them, thus A. No precipitate is formed.

Regards.

Answer:

An increase

Explanation:

The strong southerly winds affect the vapor pressure by increasing it .

When the vapor pressure increases it means an increase in temperature and more evaporation occurs.

A decrease in the vapor pressure means a reduction in temperature with less amount of evaporation being involved

Answer:

The one cell of a unicellular organism must be able to perform all the functions necessary for life. These functions include metabolism, homeostasis and reproduction. Specifically, these single cells must transport materials, obtain and use energy, dispose of wastes, and continuously respond to their environment.

Answer:

A single celled Organism is able to get energy from complex molecules, to move, and to sense their environment.

Explanation:

The ability to perform these and other functions is part of their organization.

Answer:

true.

Explanation:

The total path covered by an object during its entire journey is called the distance covered. It is equal to the sum of all path traveled.

A person runs 21.0 km west then turns around and runs 10.0 km east. The total distance covered will be the sum of 21 km and 10 km.

d = 21 km + 10 km

d = 31 km

Hence, the given statement is true.

Answer:

The temperature is always lower.

Explanation:

The temperature is always lower at the end of the state as compared to beginning of the state. We can see in the given data, the temperature is higher at the beginning i. e. 140 degree Celsius but with the passage of time, the temperature of a state decreases constantly  and the temperature at the end is lower i. e. 20 degree Celsius. So we can conclude that the temperature is always lower.

We want to study how the temperature behaves in a change of phase. Ideally, we would read a graph and use the given information, but we can't see the graph, so for the answer, I will use a general thermodynamics knowledge instead of the missing graph.

We will see that the correct option is: The temperature is always the same

---------------------------------------

Let's start by explaining how temperature manifests in objects.

Assume we have something in solid phase. As we increase the temperature, the particles on the solid increase their kinetic energy, thus, the particles move more.

This causes that the volume of the object increases (for example when we heat up a metal and it dilates). This keeps happening until we reach a critical point, when we are near a change of phase.

At this point the energy given is not used to increase the temperature of the object, but is used to "break" bonds in such a way that the particles are more free than before. When all these bonds are "broken" the change of phase is completed, and in the case of the solid, we go from solid phase to liquid phase.

An example of this is that we can have liquid water and solid water both at 0°C, so if you have a thermometer in your home, an experiment that you can do is:

Put water in the refrigerator.

Note when the liquid water reaches 0°C

As the water starts to solidify, keep recording its temperature, you will see that it does not change (a lot, it may change a little bit) until all the water changes of phase.

So to answer this;

how does the temperature at the beginning of a change of state compare with the temperature at the end of the change?

The temperature is always the same

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Answer:

noble gases

Explanation:

Group 8A — The Noble or Inert Gases. Group 8A (or VIIIA) of the periodic table are the noble gases or inert gases: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). The name comes from the fact that these elements are virtually unreactive towards other elements or compounds.

Answer:

noble gases

Explanation:

Gathering 8A — The Noble or Inert Gases. Gathering 8A (or VIIIA) of the intermittent table are the respectable gases or dormant gases: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). The name originates from the way that these components are practically lifeless towards different components or mixes.

Answer:

No

It's called a formula of an element which is a sodium element.

Answer:

[tex]m=243.72g[/tex]

Explanation:

Hello,

For the given chemical reaction:

[tex]CaO(s) + 3 C(s) \rightarrow CaC_2(s) + CO(g)[/tex]

Whose heat of reaction is 464.8 kJ/mol which means that energy is absorbed due to the chemical reaction, we can compute the moles of calcium carbide via the following relationship:

[tex]n=\frac{1770kJ}{464.8 kJ/mol}\\ \\n=3.81mol[/tex]

Then, since the molar mass of calcium carbide is 64 g/mol, the yielded mass turns out:

[tex]m=3.81mol*\frac{64g}{1mol}\\ \\m=243.72g[/tex]

Best regards.

Answer:

Lead(II) acetate trihydrate

Explanation:

hope it helps

Answer:

This question is incomplete and it lacks options. The complete question is as follows;

In condensation reactions, the atoms that make up a water molecule are from what?

a. oxygen

b. only one of the reactants

c. both of the reactants

d. carbohydrates

e. enzymes

The answer is C. Both of the reactant

Explanation:

In a chemical reaction, two small molecules called monomers combine to form a much larger molecule called polymer in a process called CONDENSATION REACTION. Some condensation reactions is characterized by the release of a water molecule (dehydration).

This water molecule is formed as a result of the active participation of both reactants. During the reaction, hydroxyll group (-OH) from one of the reactants breaks off and combines with hydrogen ion (H+) from the other reactant to form water molecule (H2O).

Hence, the atoms that make up the water molecule come from both of the reactants participating in the condensation reaction.

Answer: Since one molecule of CO2 contains one molecule carbon atoms, therefore, 0.6 molecule of carbon dioxide will contain 0.6 molecule of carbon.

Mass of C in 0.6 molecule of CO2

Explanation

= No. Of molecule × molar mass

= 0.6× 12gm

=7.2gm

Answer:

Sociologist view that an individual is a reflection of a society to which he or she have belonged.

Explanation:

It is not an individual or a society, but both of them together allows us to reveal the fundamentals of human existence. The extreme view of the person or society has been discarded for quite some time. The concept of society indicates a reciprocal giving-and-take by the individuals involved in the form of mutual corporations, interaction, or the more subtle types of social interaction such as letter writing, festival greeting, sending and accepting presents, telephone communication, e-mailing, internet chatting, and public relations engagement.

Answer:

E) water molecules can cluster about cations and anions.

Explanation:

Electrolytes are substance that when dissolved in water gives ion.which is cation and anion.

As they disolve in water the water molecules cluster about about cations and anions. As a result of the movement of ions they produce electricity.

Electrolytes are substances that dissociate into ions when dissolved in water. The correct answer is "Water molecules can cluster around cations and anions."

These ions are electrically charged particles, with cations carrying a positive charge and anions carrying a negative charge. When an electrolyte dissolves in water, the water molecules surround and interact with the ions.

Water molecules have a polar nature, with a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom. These polar water molecules can cluster around the charged ions, forming a hydration shell. The positive ends of water molecules (hydrogen atoms) are attracted to anions, while the negative ends (oxygen atoms) are attracted to cations.

This clustering of water molecules around the ions is due to the electrostatic forces of attraction between the charged particles and the polar water molecules. This phenomenon helps to stabilize the ions in solution and enables the electrolyte to dissolve readily in water.

Therefore, the correct answer is that electrolytes dissolve readily in water because water molecules can cluster around both cations and anions.

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