Which processes have a negative enthalpy change?I. 2CH3OH(l) + 3O2(g) → 2CO2(g) + 4H2O(l)II. HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)III. H2O(g) → H2O(l)A. I and II onlyB. I and III onlyC. II and III onlyD. I, II and III

To calculate the density of lead in g/cm3, you need to know the molar mass and the atomic radius of lead.

The molar mass of lead is 207.2 g/mol and the atomic radius of lead is 175 pm. The density of lead can be calculated using the formula density = molar mass/volume.

Since lead is in a face-centered cubic crystal structure, the volume of a unit cell is given by the formula volume = (4/3) × π × (atomic radius)3. Substituting the values for molar mass and atomic radius into the formula for density gives the following result: density = 207.2 g/mol / (4/3) × π × (175 x 10-12 m)3 = 11.34 g/cm3.

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A gas made from carbon and hydrogen has a density of 1. 16g/L at STP, the molar mass will be 25.984 g/mole

The standard temperature and pressure are referred to as the STP conditions. As reference values for gases, pressure values at 1 atmosphere and temperature at 0°C are utilized. And under these circumstances, a mole of any gas takes up around 22.4 liters of space.

The mass that is present per unit volume of a substance is known as its density. You understand that 1. 16 g/L indicates that this gas has a mass of 1. 16 g per liter.

Given that one mole of gas at STP takes up 22.4 litres, you can state that the mass of one mole of this gas will be:

22.4 L× 1. 16 = 25.984 g

Finally, the molar mass of this gas is 25.984 g/mole if 1 mole of it weighs 25.984 g.

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To make 2.00 liters of a 0.0500 M solution of boric acid, you would need to add 61.83 grams (1 mole) of boric acid to the solution.

Chemical solutions are solutions made up of one or more chemicals that can be used for a variety of purposes. Chemical solutions can be used for industrial, medical, and environmental applications, and can be used to clean, disinfect, treat, or otherwise modify materials. Examples of chemical solutions include cleaning agents, solvents, antifreezes, acids, bases, and salts. Chemical solutions can also be used to create pharmaceuticals, dyes, and other products.

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The  ion will form from each main‑group element in periodic table is :

Na : Na⁺

F : F⁻

N : N³⁻

I : I⁻

Sr : Sr²⁺

The periodic table will help in identifying the type of the ion that an element can form which is based on the electrons need to be gained or the lost and  become stable. The element with the positive charge means it losses the electrons to fulfil the octet rule and become stable.

The element with the negative charge show that the element gains the electrons to become stable. To becom stable the element needs to statisfy the octete rule that to have the 8 electrons in the outer most shell.

The question is incomplete, the complete question is :

Use the periodic table to predict which ion will form from each main-group element.

Na:

F:

N:

I:

Sr:

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The molarity of the ions in a 0.620 M solution of Ca(OH)₂ assuming the compound dissociates completely is molarity of the calcium ion,  Ca²⁺  = 0.620 M and molarity of the hydroxide ion, OH⁻ = 1.24 M.

The  Ca(OH)₂ dissociation reaction is as follows :

Ca(OH)₂ --->  Ca²⁺  +  2(OH⁻)

The number moles of the Ca(OH)₂  = 0.620 M

The molarity of the calcium ion,  Ca²⁺  = 0.620 M

The molarity of the hydroxide ion, OH⁻ = 2 × 0.620

The molarity of the hydroxide ion, OH⁻ = 1.24 M

Thus, the molarity of Ca²⁺  is 0.620 M and the  molarity of the hydroxide ion, OH⁻ is 1.24 M.

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Zinc will take the place of iron in the compound since it comes before iron in the activity sequence. ZnCl2 and Fe are the byproducts of this single replacement process.

A single element replaces one atom in a compound to create a new compound as well as a pure element in a single replacement reaction. In a compound, metals always replace metals and nonmetals always replace nonmetals, similar to double replacement reactions.

When pieces of two ionic compounds are swapped to create two new compounds, the process is known as a double-replacement reaction. A double-replacement equation has two chemicals acting as reactants and two separate compounds acting as products.

The relative reactivities of the two metals can be used to predict whether one metal will take the place of another metal in a complex. An activity series of metals, which groups metals in decreasing order of reactivity, can assist us in determining this.

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Answer: Compound

Explanation:

The same types of atoms combine the substance is Molecule.

What is atom ?

A substance's tiniest component that cannot be destroyed chemically. A proton (a positive particle) and a neutron (a neutral particle) make up the nucleus (center) of each atom (particles with no charge). The nucleus is filled with negative electrons. Chemical reactions cannot generate or destroy atoms since they are indivisible particles. The mass and chemical makeup of an element's atoms are the same. The masses and chemical characteristics of atoms differ amongst elements.

What is molecule?

The number of atoms that make up a molecule might vary. Pillows, sheets, and mattress toppers are now part of Molecule's growing line of sleep essentials. To give sleepers a cool, supportive surface, the Molecule AirTEC Mattress Topper blends three layers of open-cell memory foam, AirTEC foam, and polyfoam.

Therefore, the same types of atoms combine the substance is Molecule.

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The temperature dependence of the solubility of a gas in water can be rationalized in terms of the kinetic molecular theory by considering the effects of the increased temperature on the kinetic energy of the gas molecules, their rate of collisions with the water and air surfaces, and the vapor pressure of the gas in the air above the liquid.

The temperature dependence of the solubility of a gas in water can be rationalized in terms of the kinetic molecular theory as follows:

According to the kinetic molecular theory, the solubility of a gas in a liquid is directly proportional to the number of gas molecules that escape from the surface of the liquid into the air.

The solubility of a gas in water increases with increasing temperature because the increased temperature results in an increase in the kinetic energy of the gas molecules. This increased kinetic energy causes the gas molecules to move more rapidly and collide more frequently with the surface of the liquid, resulting in a greater number of gas molecules escaping into the air.

At the same time, the increased temperature also increases the vapor pressure of the gas in the air above the liquid. The vapor pressure of a gas is directly proportional to the number of gas molecules in the air, so the increased vapor pressure results in a greater number of gas molecules escaping from the air back into the water.

However, the increased kinetic energy of the gas molecules in the water also results in an increased rate of collisions between the gas molecules and the water molecules, causing the gas molecules to dissolve more readily in the water. As a result, the overall effect of the increased temperature is to increase the solubility of the gas in water.

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The osmotic pressure generated when 17.5 g of Na2Cr2O7 are dissolved in 87.4 mL of water at 298 K is 6.02 atm.

The van't Hoff factor (i) is a concept in thermodynamics that represents the number of particles into which a solute dissociates in solution. For example, when a salt dissolves in water, it can dissociate into individual ions, increasing the concentration of solute particles in solution.

The osmotic pressure generated by a solution can be calculated using the equation:

Π = iMRT

where Π is the osmotic pressure in atm, i is the van't Hoff factor, M is the molar concentration of the solute, R is the gas constant (0.08206 Latm/molK), and T is the temperature in Kelvin.

The molar mass of Na2Cr2O7 is 258.0 g/mol, so the moles of solute can be calculated as:

n = m/M = 17.5 g / 258.0 g/mol = 0.06788 mol

The molar concentration of the solution can be calculated as:

C = n/V = 0.06788 mol / 0.0874 L = 0.7738 M

Plugging these values into the equation for osmotic pressure:

Π = iMRT = 2.54 * 0.7738 M * 0.08206 Latm/molK * 298 K = 6.02 atm

So, the osmotic pressure generated when 17.5 g of Na2Cr2O7 are dissolved in 87.4 mL of water at 298 K is 6.02 atm.

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An electron pair travelling to another atom is depicted by a double-barbed arrow. The movement of a single electron from each atom to create a link between them is depicted by single-barbed arrows.

A molecule's three-dimensional structure or arrangement is a crucial aspect. The preferred spatial orientation of covalent connections to atoms with two or more bonding partners determines this form. The greatest way to view three dimensional setups is with the aid of models. A bond that is roughly in the surface plane is represented by a straightforward straight line. A hatching bond is directed behind the plane, and a wedge-shaped bond is directed in front of it (thick end facing the spectator) (away from the viewer).

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A. When the pressure of a gas is increased, its volume decreases, assuming that temperature is held constant. This relationship is described by Boyle's law, which states that the volume of a gas is inversely proportional to its pressure at constant temperature.

Boyle's Law is a gas law that describes the relationship between the pressure and volume of a gas at constant temperature. It states that the volume of a gas is inversely proportional to its pressure. Mathematically, Boyle's law can be expressed as:

V ∝ 1/P

where V is the volume of the gas and P is its pressure.

B. As the pressure of a gas is gradually increased, its volume will decrease correspondingly. The relationship between the pressure and volume of a gas can be graphed to produce a curve, which will show that as pressure increases, volume decreases, and vice versa.

This relationship can be used to predict the behavior of a gas under different conditions and is a useful tool in various fields, including engineering, thermodynamics, and physics.

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Acidity the qualities of water samples.

Acidic water is defined as having a pH lower than 7. The pH of water reveals how basic (alkaline) or acidic it is. The pH scale for this measurement runs from 0 to 14, with 7 being neutral. The United States Environmental Protection Agency (EPA) advises keeping public water within a pH range of 6.5 to 8, even though it does not control the pH of drinking water. Acidic water may be advantageous for skin, hair, and washing produce since it is thought to have antibacterial properties. It can also have a lot of unfavorable and perhaps harmful side effects. This article discusses acidic water's definition, potential drawbacks and advantages, and how to get rid of it from your drinking water.

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True , The volume of a gas grows as the pressure lowers for a certain quantity of gas at a constant temperature. The volume of a specific amount of gas at constant pressure increases as the temperature rises.

The scientific theory stating that while pressure is held constant, a certain quantity of gas expands in volume as its temperature rises is known as: a. Boyle's Law.

Boyle's Law describes the relationship between pressure and volume. The volume of a gas reduces as the pressure on it increases because the gas particles are driven closer together.

Pressure and volume are inversely related for a fixed mass of an ideal gas held at a constant temperature. Boyle's law, on the other hand, is a gas law that states.

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Answer:

Explanation:

Zn+H

2

​

SO

4

​

→ZnSO

4

​

+H

2

​

The solution will contain the remaining ions. But PbCl₂  is insoluble in water and forms precipitate

Ions are molecules or atoms that have had one or more electrons added or taken away, giving them an electric charge. They can have a neutral, positive, or negative charge. Ions with a positive charge are known as cations, while those with a negative charge are known as anions. Ions can be used to conduct electricity and play a crucial role in chemical reactions.

(a) In a liter of solution, 1M of Pb(NO₃)₂ contains 1 mol of Pb⁺² ions and 2 moles of NO₃⁻¹ ions

In a liter of solution, 1M of NaCl contains 1 mol of Na⁺¹ ions and 1 mole of Cl⁻¹ ions.

As a result, Concentration of Aqueous Nitrate ions(NO₃)= 2 mols/2 L= 1 M

Therefore, Concentration of Aqueous Na⁺¹ ions= 1mols/2 L= 0.5M

But PbCl₂  is insoluble in water and forms precipitate

b. 1M of KClO₄ contains 1 mol of K⁺ ions and 1 mol of ClO₄⁻¹ ions in 1 liter of solution.

1M of (NH₄)₂CO₃ contains 2 mol of NH₄⁺¹ ions and 1 mol of CO₃⁻² ions in 1 liter of solution.

As a result, the concentration of aqueous ammonium ions (NH₄⁺¹) is 2 mols/2 L

                                       =1 M,  

Concentration of Aqueous Carbonate ions(CO₃⁻²)= 1mol/2 L

                                   = 0.5 M

Therefore , Concentration of Aqueous potassium ions(K⁺¹)= 1mol/2 L

                                         = 0.5M

Hence , It is considered insoluble because hot water is not mentioned in the question.

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There are 0.075 moles of copper atoms in 4.5 x 10^22 atoms of Cu.

The number of moles in 4.5 x 10^22 atoms of copper can be calculated as follows:

First, we need to find the number of moles of copper atoms:

number of moles = number of atoms / Avogadro's number

number of moles = 4.5 x 10^22 atoms / 6.022 x 10^23 atoms/mol

number of moles = 0.075 mol

So, there are 0.075 moles of copper atoms in 4.5 x 10^22 atoms of Cu.

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The diversity of organic molecules is largely due to the properties of carbon atom, which allows for formation of strong covalent bonds with other elements and can form various structures, such as chains, rings, and branched structures.

The diversity of organic molecules arises from the ability of carbon atoms to form strong covalent bonds with a variety of other elements, including hydrogen, oxygen, nitrogen, and sulfur.

Carbon's ability to bond with multiple other elements, as well as its capacity for forming stable chains, rings, and branched structures, allows for the creation of a wide range of organic molecules with unique properties.

Additionally, organic molecules can undergo a variety of chemical reactions, such as substitution, addition, and elimination reactions, which further increases the diversity of organic compounds. These reactions can lead to the formation of new and complex organic molecules, as well as the modification of existing ones.

Furthermore, the presence of functional groups, such as hydroxyl, carbonyl, and amine groups, imparts specific chemical and physical properties to organic molecules, further contributing to their diversity.

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Acetylcholine acts on preganglionic neurons in the sympathetic and parasympathetic systems of the autonomic nervous system to govern a variety of processes within the autonomic system. Thus, it is true.

Muscles. Drugs that affect acetylcholine can have varying degrees of movement disturbance or even paralysis because this neurotransmitter is crucial for muscular function.

This neurotransmitter functions to activate muscles in the peripheral nervous system and is a key component of the autonomic nervous system.

Therefore, it is true that Acetylcholine serves as the neurotransmitter in the peripheral nervous system that carries messages from motor nerves to skeletal muscles.

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Acetylcholine acts on neurons in the sympathetic and parasympathetic systems of the autonomic nervous system to govern a variety of processes within the autonomic system. Thus, it is true.

Muscles. Drugs that affect acetylcholine can have varying degrees of movement disturbance or even paralysis because this neurotransmitter is crucial for muscular function.

This neurotransmitter functions to activate muscles in the peripheral nervous system and is a key component of the autonomic nervous system.

Therefore, it is true that Acetylcholine serves as the neurotransmitter in the peripheral nervous system that carries messages from motor nerves to skeletal muscles.

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Answer: x will be the element cobalt

The correct transcription of mRNA from DNA is important because mRNA serves as a blueprint for the production of proteins in the human body.

The sequence of nucleotides in mRNA determines the specific sequence of amino acids in a protein. The specific codon, or sequence of three nucleotides, in mRNA correspond to a specific amino acid.

For example, the codon for valine is GCA. If the mRNA is transcribed incorrectly and the codon for valine is changed, a different amino acid may be incorporated into the protein being produced, leading to a potentially non-functional or even harmful protein.

This highlights the importance of accurate transcription for the proper functioning of proteins and, therefore, the growth and maintenance of the human body.

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This implies that the CO2 molecule does not include any lone pairs.

According to the Lewis structure of CO2, which stands for carbon dioxide, there are two double bonds between each oxygen atom and the carbon atom. The arrangement of the atoms and the distribution of electrons within a molecule are represented by the Lewis structure of the molecule.

The core carbon atom in the Lewis structure of CO2 is surrounded by two oxygen atoms.

Each link in the Lewis structure is represented by a pair of dots, and the quantity of valence electrons on each atom is specified. Each oxygen atom in CO2 possesses six valence electrons, compared to the four valence electrons on the carbon atom.

Each link in the Lewis structure is represented by a pair of dots, and the quantity of valence electrons on each atom is specified. Each oxygen atom in CO2 possesses six valence electrons, compared to the four valence electrons on the carbon atom.

There are no additional electrons that may be referred to as "lone pairs" in a double bond because two pairs of electrons are shared between two atoms.

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.

When a substance is added to a solvent, two processes take place: dissolving and dissociating. A solid substance is said to dissolve when it is equally distributed throughout a solvent to create a homogenous solution. The process by which a chemical separates into its constituent ions in a solution is referred to as dissociating, on the other hand.

The number of ions that a compound dissociates into when it is dissolved in a solvent is measured by the van't Hoff factor, also referred to as the ionization factor. For instance, the van't Hoff factor of table salt (NaCl), which dissociates into two ions in water (Na+ and Cl-), is 2. Contrarily, when sugar (sucrose) is dissolved in water, it does not separate into ions, hence its van't Hoff factor is 1.

The van't Hoff factor can typically be calculated experimentally by measuring the osmotic pressure or elevation of the solution's boiling point. A chemical that dissociates into ions in solution is indicated by a van't Hoff factor greater than 1, whereas a compound that does not disintegrate into ions is indicated by a van't Hoff factor equal to 1.

At equilibrium, the rates of the forward and reverse reactions are equal, meaning that the products are being formed at the same rate as they are being consumed.

As a result, there is no change in the concentration of the reactants or products over time. This is so because the chemical reaction is balanced, and any change in a substance's concentration would cause an imbalance, which would cause the reaction to shift until the new balance was reached. To put it another way, if the concentration of one drug rises, the reaction will change to eat it up until the concentration falls to a point where it is balanced with the other components in the reaction mixture.

The reaction will change to produce more of the substance in question whenever the concentration of that substance decreases. As a result, at equilibrium, a mixture's concentrations are constant.

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The acetone solution has a molality of 9.76 mol/kg in an aqueous solution.

The solution has a molality of 4.1. We know that we have 13 g of HCl in 100 g of solution because to the 13% solution's mass. It is necessary to convert the 13 g of HCl into moles using its molar mass, which is 1.01 + 35.45 = 36.46 g/mol g / m o l.

We can first convert the percentage of acetone by mass to grammes of acetone as follows:

36.1% by mass = 36.1 g acetone / 100 g solution

Next, we can find the mass of water in the solution:

100 g solution - 36.1 g acetone = 63.9 g water

Now, we can find the number of moles of acetone:

36.1 g acetone / 58.08 g/mol = 0.622 mol acetone

Finally, we can calculate the molality of the solution:

0.622 mol acetone / (63.9 g water / 1000 g/kg) = 9.76 mol/kg

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When the Red Blood Cell is moved to a Solution of 0.1% Nacl the cell will swell by Endosmosis and finally may burst.It is a type of Osmosis

Osmosis is a method of passive transport in which solutions move from a region of high solute concentration to low solute concentration. Based on Concentration or Tonicity the solutions can be of 3 types Hypertonic - When cells are placed in High solute concentration the solvent will move outside due to exosmosis.

Hypotonic-When the concentration of solution is less than that of inside the cell.

Isotonic - Same concentration inside and outside the cell.

0.1% means low solute concentration, when a cell is placed in Hypotonic- The water will move into the cell and the cell will swell up.

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The potential impact that an unbalanced force can have on an object in motion is that an unbalanced force can change both the object's direction and speed (option C).

Newton's first law of motion states that an object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force.

An unbalanced force is the resultant force acting on a body is not equal to zero that is capable of bringing about motion.

According to this question, an unbalanced force is capable of changing the direction and speed of an object in motion.

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The reason an oxygen atom (with 8 protons) stays close to zero charge after making two covalent bonds is due to the sharing of electrons between the two bonded atoms.

A covalent bond is a type of chemical bond that results from the sharing of one or more pairs of electrons between two atoms. In a covalent bond, the electrons are shared equally between the two atoms, resulting in a stable bond that holds the atoms together.

Covalent bonds are formed between atoms that have similar electronegativities, meaning that they have a similar attraction for electrons. When atoms with similar electronegativities bond, they share electrons to fill their valence electron shells and attain the electron configuration of a noble gas, which is a highly stable configuration.

Covalent bonds are very strong and can only be broken by the transfer of electrons or by applying a significant amount of energy, such as heat or light. Covalent bonds are found in many types of molecules, including organic compounds, water, and gases like hydrogen and oxygen.

In a covalent bond, electrons are shared between atoms to form a shared electron pair that is attracted to the nuclei of both atoms. This shared electron pair acts as a bridge between the two atoms, forming a strong bond between them.

By sharing electrons, the oxygen atom has filled its valence shell (the outermost shell containing electrons) with 8 electrons. This satisfies the octet rule, which states that atoms tend to form bonds in such a way that they have 8 electrons in their valence shell.

As a result of the shared electrons, the overall charge of the oxygen atom stays close to zero, as the negatively charged electrons are evenly distributed around the positively charged nucleus. This balance of charges results in a neutral oxygen atom with close to zero charge.

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Since the ore is 31.1% nickel by mass, every 100 g of the ore contains 31.1 g of nickel. To have 70.0 g of nickel, we need  2.25 kg of the ore.

When we say that ore is 31.1% nickel by mass, we mean that 31.1 g of nickel is present in every 100 g of the ore. We can use this information to calculate the amount of ore needed to obtain a certain amount of nickel.

To find the amount of ore needed to get 70.0 g of nickel, we can divide the desired amount of nickel by the amount of nickel present in 100 g of the ore:

70.0 g / (31.1 g/100 g) = 70.0 g / 0.311 = 2.25 kg

So, we would need to dig up 2.25 kg of the ore to get 70.0 g of nickel.

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No, it's a bad idea to boil NaOH in a beaker. Even a dilute solution of NaOH will attack and etch glass at its boiling point.

When boiling NaOH, the solid dihydrate might melt straightly into a solution at 13.35 °C; however, boiling once the temperature exceeds 12.58 °C. it often decays into a solid monohydrate and a liquid solution. As it boils it will get more concerted and the NaOH corrosive effect will concentrate on a smaller top area. The solution may splatter or boil. Here is how to build a sodium boiling hydroxide solution safely, along with recipes for several common.

The dissolution of NaOH sodium hydroxide in water is conducted by the release of an amount of heat because the solvation of hydroxide ions and sodium ions is most exothermic. Solvation is the NaOH proceed by which ions in a solid boiling dissociate from each other and interact with water molecules.

So we can conclude that The solubilization curve tends to boil to carry lower NaOH concentration with the increase in temperature

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It's essential to wear protective equipment such as gloves and goggles when handling sodium hydroxide as it is a strong base and can cause skin irritation.

What is sodium hydroxide?

Sodium hydroxide is an inorganic compound with the formula NaOH.

To prepare a 250 cm^3 solution of 0.04 mol sodium hydroxide, you would need the following steps:

Therefore, It's essential to wear protective equipment such as gloves and goggles when handling sodium hydroxide as it is a strong base and can cause skin irritation.

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