Which elements are liquid at room temperature

Answer:

PATHOGEN.

Explanation:

In biology, pathogen refers to any organism or particle that is capable of causing infectious diseases. Thus, all the microbes that cause diseases such as bacteria, virus, fungi, viroid,  etc are collectively known as pathogen. The entrance of pathogen into the human body usually stimulate the immune system. The immune system functions by recognizing pathogens and by capturing and destroying them.

Answer:

0.60 L.

Explanation:

How many moles of [tex]\rm H_2SO_4[/tex]?

[tex]n(\mathrm{H_2SO_4}) = c\cdot V = 4.0\times 0.30 = \rm 1.2\; mol[/tex].

How many moles of [tex]\rm NaOH[/tex] will react with all that 1.2 moles of [tex]\rm H_2SO_4[/tex]?

Balance the equation:

[tex]\rm H_2SO_4 + 2\; NaOH \to Na_2SO_4 + 2\;H_2O[/tex].

The coefficient in front of [tex]\rm H_2SO_4[/tex] is 1. The coefficient in front of [tex]\rm NaOH[/tex] is 2. Hence the ratio:

[tex]\displaystyle \frac{n(\mathrm{NaOH})}{n(\mathrm{H_2SO_4})} = \frac{2}{1} = 2[/tex].

Therefore

[tex]\displaystyle n(\mathrm{NaOH}) = \frac{n(\mathrm{NaOH})}{n(\mathrm{H_2SO_4})} \cdot n(\mathrm{H_2SO_4}) = 2\times 1.2 = \rm 2.4\;mol[/tex].

What will be the volume of the [tex]\rm NaOH[/tex] solution?

[tex]\displaystyle V(\mathrm{NaOH}) = \frac{n}{c} = \frac{2.4}{4.0} = \rm 0.60\;L[/tex].

The correct answer is B).

Answer:

B) use 0.2 M HCl

Explanation:

Lowering the concentration of a reactant will slow down the rate of reaction. If she would use 0.2 M HCl, the reaction rate will be slower than with 1.0 M HCl. The other choices would increase the rate of reaction, making it even more dangerous.

Answer:

f

Explanation:

pressure

Answer:

0.1589 mol ≅ 0.16 mol.

Explanation:

no. of moles (n) = mass/molar mass

mass of Al(OH)₃ = 12.4 g & molar mass of Al(OH)₃ = 78.01 g/mol.

∴ n = mass/molar mass = (12.4 g)/(78.01 g/mol) = 0.1589 mol ≅ 0.16 mol.

Answer:

Explanation:

1) Word reaction:

This is a single replacement reaction, in which aluminum, a more acitve metal than iron, replaces the iron in the ferrous oxide to form aluminum oxide and iron.

2) Skeleton chemical equation:

3) Balanced chemical equation:

Add the coeffcients to comply with the law of conservation of mass:

4) Mole ratio of Al and FeO:

5) Set a proportion with the unkown and solve:

Answer:

A saturated solution

Explanation:

A saturated solution is a solution which has dissolved as much solute as it can dissolve at a given temperature. If more solutes are added, a saturated solution would not dissolve it. Such solution has reached its carrying capacity.

If the temperature changes, the solution might be able to dissolve more solutes in it.

An undersaturated solution is one in which does not contain enough dissolved solutes in it at a given temperature.

Answer:

its d 3.9 not c

Explanation:

To find the maximum amount of magnesium oxide produced during the reaction, we need to determine the limiting reactant and calculate the moles of magnesium oxide produced. Using the mole ratio and converting grams to moles, we find that the maximum amount is 3.99 grams.

To determine the maximum amount of magnesium oxide that can be produced during the reaction, we need to find the limiting reactant. First, we convert the given masses of magnesium and oxygen to moles using their respective molar masses. The balanced chemical equation tells us that the mole ratio of magnesium to magnesium oxide is 1:1, so the number of moles of magnesium is equal to the number of moles of magnesium oxide. Lastly, we convert the moles of magnesium oxide to grams using its molar mass to find the maximum amount of magnesium oxide that can be produced.

Therefore, the maximum amount of magnesium oxide that can be produced during the reaction is 3.99 grams.

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Answer: It contracts  and its density decreases, I believe.

Explanation:

Answer:

its density decreases

Explanation:

Answer:

All of the above

Explanation:

Panthers, pumas, and mountain lions are all the same animal. Just different names. So, all of these would be correct.

Final answer:

The greatest amount of ammonium carbonate is produced when reactants NH3, CO2, and H2O are used in the mole ratio of 2:1:1, ensuring an excess of water.

Explanation:

To determine the reactant quantities that would result in the greatest amount of ammonium carbonate being formed, we must look at the stoichiometry of the balanced chemical equation provided:

2NH3(g) + CO2(g) + H2O(l) → (NH4)2CO3

According to this equation, therefore, the greatest amount of ammonium carbonate will be produced when reactants are supplied in the mole ratio of 2:1:1 for NH3:CO2:H2O, respectively. Choosing reactant quantities that provide ammonia and carbon dioxide in at least this ratio, while ensuring an excess of water, would maximize production of ammonium carbonate.

Answer: The theories are such that if any chemical produce H+ ion then it is an acid and if the chemical produces OH- ion then it's a base.

Explanation:

sorry I am not that much knowledgeable like all of you

The degree of certainty is high.

Answer:

The correct answer is "high".

Explanation:

Taphonomy is the science that studies how organic matter decays and becomes fossilized. Forensic taphonomy is used to estimate the characteristics of a person's death, with tests with levels of certainty depending on multiple factors. If a sample has a short PMI (Postmortem Interval), warm and humid conditions, the degree of certainty is probably high because the conditions are ideal to preserve an organic sample.

Answer: since it has a very reactive sulfhydryl group at its side chain. This puts cysteine in special position that cannot be replaced or substituted by any other amino acid. Because disulfide bridges formed by cysteine residues are permanent component of protein primary structure.

Explanation:

The question asks for the product structure of a reaction to be drawn using a utility. Somewhat, it isn't possible to provide a drawn response without the reaction details and the specific utility. However, in general, recognizing the reactants, the type of reaction, and consequently sketching the product guidance was given.

The current question pertains to a chemical reaction product and the drawing of its structure using a specific utility. Unfortunately, without an image of the reaction and the platform's drawing utility unattainable here, an explicit 'drawn' response isn't feasible. However, the request to not specify stereochemistry suggests that your interest is mainly in the skeletal structure.

Generally, in organic chemistry, you'd discern the reactants, identify the type of reaction (such as addition, substitution, or elimination), and consequently draw the product by connecting atoms according to the reaction rules. The stereochemistry, which refers to the three-dimensional arrangement of the atoms, isn't a concern in this case.

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Answer:

Lithium

Explanation:

An ionic bond requires one metal and one nonmetal. Out of all the choices given, Lithium is the only one that is a metal.

hydrogen is the most

Hydrogen is the most abundant element in the universe, making up about 90% of atoms. Helium is the second most abundant. These two elements dwarf the prevalence of all other elements combined.

The most abundant chemical element in the universe is hydrogen. Accounting for approximately 90% of atoms, hydrogen's prevalence surpasses all other elements. This elemental dominance extends to the composition of stars, including our sun, where hydrogen serves as a primary fuel for stellar processes. Following hydrogen, helium constitutes most of the remaining 10%, and all other elements appear in far lesser quantities. Hydrogen plays a significant role on Earth as well, being a part of countless compounds such as water, which is the most widespread compound of hydrogen on our planet.

Cholesterol is an example of a lipid.

Cholesterol is an example of a(n) lipid. Hence, option C is correct.

A lipid is any of various organic compounds that are insoluble in water.

Cholesterol is one of several types of fats (lipids) that play an important role in your body.

Cholesterol is a waxy substance found in all cells of the body.

The body needs it to make hormones, Vitamin D, and substances that aid in digestion.

The liver makes all the cholesterol needed for these functions.

Hence, option C is correct.

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Answer:

ions

Explanation:

An atom that has gained or lost an electron is called an ion. Ions are charged particles that have lost or added an electron to their outermost shell. Ions are the basis of any chemical reaction. The combination of ions leads to the formation of bonds between atoms and this results in molecules and compounds.

When atoms are in their ground state, they are otherwise neutral and such would not combine chemically. It is difficult to find elements in such form naturally. Atoms that have ionized by losing or gaining electrons would freely combine with one another in order to establish a more stable configuration.

Answer:

40.73 L.

Explanation:

where, P is the pressure of the gas in atm (P = 121.59 kPa/101.325 = 1.2 atm).

V is the volume of the gas in L (V = ??? L).

n is the no. of moles of the gas in mol (n = 2.0 mol).

R  is the general gas constant (R = 0.082 L.atm/mol.K),

T is the temperature of the gas in K (T = 25°C + 273 = 298 K).

∴ V = nRT/P = (2.0 mol)(0.082 L.atm/mol.K)(298 K)/(1.2 atm) = 40.73 L.

Answer:

C. the last one

Explanation:

Cysteine's unique characteristic is its ability to form disulfide bridges, covalent bonds that provide structural stability to proteins. The formation of these bridges is a unique property of cysteine among the amino acids, even though it, like others, can form hydrogen bonds.

The unique characteristic of the amino acid cysteine is its ability to form disulfide bridges. These bridges are covalent bonds that provide structural stability to proteins. While cysteine is capable of forming hydrogen bonds like other amino acids, its special characteristic is indeed the formation of these disulfide bridges. Two cysteine residues can come together to form a disulfide bridge, helping to stabilize the three-dimensional structure of the protein. It is notable that hydrogen bonds are weak interactions that occur broadly between many different molecules, but the covalent bonding of disulfide bridges is a unique property of cysteine within the amino acid series.

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Answer:

[tex]\boxed{\rm \text{[ClO$_{2}^{-}$] increases}}[/tex]

Explanation:

At the beginning, you have two reactions happening:

[tex]\rm HCl + H$_{2}$O$ $\, \longrightarrow \,$ H$_{3}$O$^{+}$ + Cl$^{-}$\\\rm HClO$_{2}$ + H$_{2}$O$ $\, \rightleftharpoons \,$ H$_{3}$O$^{+}$ + ClO$_{2}^{-}$[/tex]

As you add KOH(aq), it does two things:

A) The HCl is completely ionized. The Cl⁻ does not react, but it is diluted when the volume of the solution increases. [Cl⁻] decreases.

B) The KOH reacts with the H⁺ and removes it from the solution. [H⁺] decreases.

C) When all the H⁺ from the HCl has been neutralized, the KOH starts neutralizing the H⁺ from the HClO₂. According to Le Châtelier's Principle, more HClO₂ will dissociate to replace the decreased H⁺. [HClO₂] decreases.

D) As HClO₂ reacts, it forms ClO₂⁻. [tex]\boxed{\rm \textbf{[ClO$_{2}^{-}$] increases}}[/tex]

The amount of ClO2- increases as aqueous KOH is added.

Strong acids ionize completely in solution to produce hydrogen ions.

Weak acids only ionize partially in solution to produce hydrogen ions.

When aqueous KOH is added to a mixture of HCl and HClO2, the follow occurs:

Therefore, the amount of ClO2- increases as aqueous KOH is added.

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Answer:

12.5 atm.

Explanation:

Ptotal = P1 + P2 + … + Pn.

∴ Ptotal = P of gas 1 + P of gas 2 + P of gas 3 + P of gas 4 + P of gas 5.

∴ Ptotal = 5(2.5 atm) = 12.5 atm.

Answer:I believe your answer would be option B) dilute. Hope this helps.

Explanation:

The correct answer is B) Dilute

Explanation:

In a solution, the proportions of the solute vs the solvent determine the type of solution that includes dilute/concentrated or unsaturated, saturated and supersaturated. In the case of a dilute solution, this occurs if there is a small amount of the solute in comparison to the amount of solvent, which makes it possible to add more solute as this can be dissolved. This type of solution applies to the case presented because one gram of salt (solute or substance dissolved) is a small quantity of solute in comparison to the amount of solvent (the substance that dissolves) that in this case is 100 liters of water. Thus, in this case, there is a dilute solution.

Answer:

Bromine.

Explanation:

That is bromine which is a dark red vaporous liquid with a bad smell. There are only 2 elements which are liquid at room temperature, bromine and mercury.

Answer:

1.5 mol.

Explanation:

Using cross multiplication:

1.0 mole of H₂ contains → 6.022 x 10²³ molecules.

??? mole of H₂ contains → 9.03 x 10²³ molecules.

∴ The no. of moles of H₂ contains (9.03 x 10²³ molecules) = (1.0 mol)(9.03 x 10²³ atoms)/(6.022 x 10²³ atoms) = 1.5 mol.

To find the total number of moles of hydrogen gas in 9.03 × 10²³ molecules, you divide the number of molecules by Avogadro's number (6.022 × 10²³ molecules/mole), resulting in approximately 1.5 moles of hydrogen gas.

To calculate the total number of moles of hydrogen gas (H₂) from the given number of molecules, we use Avogadro's number, which is 6.022 × 10²³ molecules per mole. The number of moles (n) is given by the formula:

n = {Number of molecules} ÷ {Avogadro's number}

Substituting our values, we get:

n = (9.03× 10²³ molecules ÷ 6.022 × 10²³ molecules/mole) ≈ 1.5 moles

Therefore, there are approximately 1.5 moles of hydrogen gas contained in 9.03 × 10²³ molecules of hydrogen gas.

Hi there,

Your answer is given in the image attached above

Answer:

Option B. 20 oC

Explanation:

Thinking process:

The initial reaction takes place at: 0.01840 M/s at 25 oC.

However, the rate must be reduced to 0.0046 M/s.

It is most likely that a temperature of 20 °C is used her. This is because it offers sufficient kinetic energy to effect the reaction rate of the reaction substances.

Answer:

Rate 1 => 1.2E-3 M/s, Rate 2 => 1.05E-3 M/s, Rate 3 => 8.9E-4 M/s

Explanation:

Rate = Δ[N₂O₅]/Δtime

Rate 1 = (1.86556 - 2310195)M/(195 - 0)s = -1.2 x 10⁻³ M/s

Same for Rates 2 & 3.

The rate of reaction can be calculated in terms of the consumption of the reactants in the reaction.

In the given equation [tex]\rm N_2O_5[/tex] has been the reactant that has been used 2 moles.

The rate of the reaction has been = [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{dN_2O_5}{dt}[/tex]

Reaction rate = [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{1.86556\;-\;2.10195}{195\;s\;-\;0\;s}[/tex]

= [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{-0.23639}{195\;s}[/tex]

= 0.0006 M/s.

Reaction rate = [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{1.48825\;-\;1.86556}{556\;s\;-\;195\;s}[/tex]

= [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{-0.416735}{361\;s}[/tex]

= 0.0005 M/s

= [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{1.25\;-\;1.48825}{825\;s\;-\;556\;s}[/tex]

= [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{-0.23825}{269\;s}[/tex]

= 0.0004 M/s.

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Answer:

113.8g

Explanation:

Statement of problem: mass of 1.946mole of NaCl

Given parameters:

Number of moles of NaCl = 1.946mole

Unknown: mass of NaCl

Solution

To find the mass of NaCl, we apply the concept of moles which expresses the relationship between number of moles and mass according to the equation below:

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

To find the molar mass of NaCl:

                         the atomic mass of Na = 23g

                                atomic mass of Cl = 35.5g

                Molar mass of NaCl = (23 + 35.5) = 58.5gmol⁻¹

Mass of NaCl = Number of moles x molar mass of NaCl

Mass of NaCl = 1.946 x 58.5 = 113.8g

There would be approximately 113.72 grams in 1.946 moles of NaCl. This is calculated by using the molar mass of NaCl (58.44 g/mol) and multiplying it by the number of moles given.

To find out how many grams are in 1.946 moles of NaCl, you need to use the molar mass of NaCl. The molar mass is the mass of one mole of a substance and for NaCl, it is calculated by adding the atomic masses of Sodium (Na) and Chlorine (Cl), which is approximately 58.44 grams per mole. Therefore, to find out the mass in grams of 1.946 moles of NaCl, you multiply 1.946 moles by the molar mass of NaCl, 58.44 g/mol.

1.946 moles NaCl * 58.44 g/mol NaCl = 113.72 grams NaCl

So, 1.946 moles of NaCl is approximately equal to 113.72 grams.

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The work performed by the chemists can be considered as the useful effect to fix a problem, while some work found to harm the environment. Thus, option C is correct.

Chemists are the group of individuals that deal with the drugs and the medicines. The research made the development of the new drugs and the compounds that are used by the population to treat several diseases.

The chemicals dealt by chemist are formed to be sensitive, and can be used to fix the problems, while sometimes the effect creates the compound that harm the environment.

Thus, option C is correct.

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