The drinking water in Saplingville was found to contain 13 ppb (parts per billion) of lead. What is the concentration of lead in molarity?

(i) To calculate the molar concentration of sodium hydroxide, we first need to calculate the number of moles of sodium hydroxide in the solution. The molar mass of NaOH is 40.0 g/mol.

Number of moles of NaOH = Mass of NaOH / Molar mass of NaOH

= 0.93 g / 40.0 g/mol

= 0.02325 mol

Volume of solution = 75.0 cm³ = 0.075 L

Molar concentration of NaOH = Number of moles of NaOH / Volume of solution

= 0.02325 mol / 0.075 L

= 0.31 M

Mass concentration of NaOH = Mass of NaOH / Volume of solution

= 0.93 g / 0.075 L

= 12.4 g/L

(ii) To calculate the molar concentration of hydrochloric acid, we first need to calculate the number of moles of HCl in the solution. The molar mass of HCl is 36.5 g/mol.

Number of moles of HCl = (Volume of HCl gas x Density of HCl gas) / Molar mass of HCl

= (240.0 cm³ x 1.639 g/L) / 36.5 g/mol

= 10.75 mol

Volume of solution = 100.0 cm³ = 0.100 L

Molar concentration of HCl = Number of moles of HCl / Volume of solution

= 10.75 mol / 0.100 L

= 108 M

Mass concentration of HCl = (Molar concentration of HCl x Molar mass of HCl) / Density of solution

= (108 mol/L x 36.5 g/mol) / 1.00 g/cm³

= 3942 g/L

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To find the empirical formula of the titanium chloride, we need to use the given information to determine the moles of titanium and chlorine in the original compound, and then use those values to find the simplest whole-number ratio of atoms in the empirical formula.

First, we can find the moles of titanium in the original compound using the mass of the titanium metal produced:

mass of titanium metal = 0.819 g

molar mass of titanium = 47.867 g/mol

moles of titanium = mass of titanium metal / molar mass of titanium

moles of titanium = 0.819 g / 47.867 g/mol

moles of titanium = 0.0171 mol

Next, we can use the law of conservation of mass to find the moles of chlorine in the original compound:

moles of chlorine = moles of titanium

Now we can find the mass of chlorine in the original compound using the moles of chlorine and the molar mass of chlorine:

moles of chlorine = 0.0171 mol

molar mass of chlorine = 35.453 g/mol

mass of chlorine = moles of chlorine x molar mass of chlorine

mass of chlorine = 0.0171 mol x 35.453 g/mol

mass of chlorine = 0.606 g

Finally, we can use the masses of titanium and chlorine to find the empirical formula of the titanium chloride. The empirical formula gives the simplest whole-number ratio of atoms in a compound, so we need to divide the masses of each element by their respective atomic masses to get the number of moles of each element:

moles of titanium = 0.0171 mol

moles of chlorine = 0.606 g / 35.453 g/mol = 0.0171 mol

The ratio of titanium to chlorine is 1:1, so the empirical formula of the titanium chloride is TiCl₁, or simply TiCl.

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The total number of moles, to the nearest tenth, of solute contained in 0. 50 liter of 3. 0 M HCl is 1.5 moles.

To determine the total number of moles of solute in a solution, we need to use the formula:

moles of solute = Molarity x volume in liters

Given that we have a 0.50 L solution of 3.0 M HCl, we can simply substitute the values in the formula to obtain:

moles of HCl = 3.0 mol/L x 0.50 L = 1.5 moles of HCl

Therefore, there are 1.5 moles of HCl in 0.50 liters of 3.0 M HCl solution. We can round this to the nearest tenth, giving us a final answer of 1.5 moles of HCl.

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Answer:

They forge heavy elements in their cores, explode as supernovas, and expel these elements into space.

Explanation:

This indicates that the system's energy drops while the energy of the environment grows. As a result, the ultimate temperature is projected to be greater than the beginning temperature of 28 degrees Celsius.

The process sends heat into the environment since it is exothermic. The heat produced by the reaction is transferred to the surrounding environment, raising the temperature.

This is due to the fundamental rule of thermodynamics, which states that energy cannot be created or destroyed, but only moved from one form to another. In this case, the energy released by the reaction is transferred to the surrounding environment as heat energy, causing the temperature to rise.

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The mass of a sample of NH₃ containing 3.80 × 10²⁴ molecules of NH₃ is the product of the number of moles and the molar mass of NH₃.

To find the mass of a sample of NH₃ containing 3.80 × 10²⁴ molecules of NH₃.

Step 1: Determine the number of moles of NH₃
We know that there are 6.022 × 10²³ molecules in one mole of any substance (Avogadro's number). To find the number of moles of NH₃, divide the given number of molecules by Avogadro's number:
Number of moles = (3.80 × 10²⁴ molecules) / (6.022 × 10²³ molecules/mol)

Step 2: Calculate the molar mass of NH₃
NH₃ consists of one nitrogen (N) atom and three hydrogen (H) atoms. The atomic mass of nitrogen is approximately 14 g/mol, and the atomic mass of hydrogen is approximately 1 g/mol. So the molar mass of NH₃ is:
Molar mass of NH₃= (1 × 14 g/mol) + (3 × 1 g/mol) = 14 + 3 = 17 g/mol

Step 3: Find the mass of the sample
Now that we know the number of moles and the molar mass, we can find the mass of the sample by multiplying the two values:
Mass of the sample = Number of moles × Molar mass of NH₃

The mass of a sample of NH₃ containing 3.80 × 10²⁴ molecules of NH₃ is the product of the number of moles (calculated in step 1) and the molar mass of NH₃ (calculated in step 2).

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Answer:

7.3

Explanation:

The best way to cook a spiral ham without drying it out is to use the low and slow method.

A method is a procedure or a technique used to produce the intended results. It is a methodical technique to problem solving that entails dividing a task into smaller components and carrying them out in a specified manner.

Methods are employed in every aspect of life, including commerce, engineering, and mathematics. In the sciences, where the scientific method is applied to test hypotheses and derive conclusions, methods are particularly crucial.

This entails cooking the gammon for a longer amount of time (approximately 15 minutes per pound) at a low temperature (about 325°F). Remove the gammon from its plastic wrapper before cooking it, and set it in a shallow roasting pan.

After that, cover the ham with foil, making sure that it is tightly sealed. Then, place the ham in the oven and cook it for the recommended length of time. Lastly, about 10 minutes before the end of the cooking time, remove the foil and brush the ham with a glaze of your choosing. This will help add flavor and moisture to the ham and help keep it from drying out.

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When working with a heat source, one should always assume that glassware and metal objects are hot. Option A is correct.

Working with a heat source requires special precautions to ensure safety in the laboratory. Heat sources such as Bunsen burners, hot plates, and ovens can generate high temperatures that can cause burns or fires if not handled properly. One important safety rule when working with a heat source is to assume that glassware and metal objects are hot.

This means that one should avoid touching or handling these objects without protective equipment, even if they appear to be cool or inactive. This is because they may still be hot from exposure to the heat source and can cause burns or injuries. Other safety measures when working with a heat source include using appropriate personal protective equipment, such as heat-resistant gloves and safety goggles, and ensuring good ventilation in the laboratory to prevent exposure to fumes or volatile chemicals. Option A is correct.

What should you do when working with a heat source?

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Electronic configuration of  Ba²⁺ is 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶; Ca²⁺ is 1s²2s²2p⁶3s²3p⁶; Li⁺ is 1s²; K⁺ is 1s²2s²2p⁶3s²3p⁶; Na⁺ is 1s²2s²2p⁶; Sr²⁺is  1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶.

Electronic configuration of the elements present in the periodic table is defined as the designation of atoms on the basis of the electrons present in their shells and subshells. The electrons entering in the same valence shell are grouped together which shows similarity in case of physical and chemical properties. Atoms tend to lose electron and attain stable positive charge so as to attain their nearest noble gas configuration.

Electronic configuration of

Ba²⁺ = 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶

Ca²⁺= 1s²2s²2p⁶3s²3p⁶

Li⁺=1s²

K⁺ = 1s²2s²2p⁶3s²3p⁶

Na⁺ = 1s²2s²2p⁶

Sr²⁺=  1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶

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Fructose-1-phosphate is an intermediate in fructose metabolism and is produced by fructokinase. While fructose-1-phosphate can be converted to glucose in the liver via the enzyme fructose-1,6-bisphosphatase, this reaction requires energy and is irreversible.

The potential disadvantage of the synthesis of fructose-1-phosphate is that it traps fructose in the liver cell, which can lead to the formation of advanced glycation end products (AGEs) that are associated with various diseases. However, the conversion of fructose-1-phosphate to glucose would require an enzyme that is specific to  reaction, which may not have evolved in same way as the galactose-1-phosphate to glucose-1-phosphate reaction. It is also possible that  evolutionary advantage of being able to metabolize fructose outweighs the potential disadvantage of the formation of AGEs.

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The freezing point of the solution is approximately 1.06306 °C

The freezing point of a solution of 0.300 mol of lithium bromide in 525 mL of water would be lower than the freezing point of pure water. The exact freezing point depression can be calculated using the formula ΔTf = Kf·m, where ΔTf is the freezing point depression, Kf is the freezing point depression constant of water (1.86 °C/m), and m is the molality of the solution. To find the molality of the solution, we need to convert the volume of water to mass using its density (1 g/mL), which gives us 525 g of water. Then, we can calculate the molality as:

molality = moles of solute/mass of solvent in kg
             = 0.300 mol / 0.525 kg
             = 0.571 mol/kg

Substituting this value into the freezing point depression formula, we get:

ΔTf = 1.86 °C/m x 0.571 mol/kg
      = 1.06306 °C

Therefore, the freezing point of the solution would be lowered by 1.06 °C compared to pure water.

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From the calculations, we can see that the mass of the acetic acid that is produced is 28.2 g.

In a chemical reaction involving two or more reactants, the limiting reactant is the reactant that is consumed completely, thereby limiting the amount of product that can be formed. The other reactant(s) that remain after the limiting reactant is completely consumed are called excess reactants.

Number of moles of CH3CHO = 20.8g/44 g/mol

= 0.47 moles

Number of moles of O2 = 14.5 g/32 g/mol

= 0.45 moles

If 2 moles of CH3CHO reacts with 1 mole of O2

0.47 moles of CH3CHO would react with 0.47 * 1/2

= 0.24 moles

Thus CH3CHO is the limiting reactant

Mass of the acetic acid produced = 0.47 moles * 60 g/mol

= 28.2 g

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Ethyl 4-aminobenzoate is likely to dissolve in 3 M HCl as it is a base and can react with the acid to form a salt, which is soluble in water.

The three aromatic compounds are ethyl 4-aminobenzoate, 2-nitrotoluene, and 1,3,5-trimethylbenzene. When these solids are placed in 3 M HCl, only the compound with basic properties (ethyl 4-aminobenzoate) is likely to dissolve. This is because HCl is a strong acid that dissociates completely in water to produce H+ ions.

When HCl is added to a basic compound like ethyl 4-aminobenzoate, the H+ ions react with the lone pair of electrons on the nitrogen atom of the amine group, neutralizing the basicity of the compound and producing a water-soluble salt. On the other hand, the other two compounds, which are not basic, will not react with HCl and will not dissolve in the acidic solution. Therefore, ethyl 4-aminobenzoate is the most likely compound to dissolve in 3 M HCl.

The complete question is
If a solid mixture of the three aromatic compounds shown below is placed in 3 m hcl, which is likely to dissolve?

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The actual yield was 1.329 g Ag.

The balanced equation for the reaction between Zinc and Silver Nitrate is:

Zn + 2AgNO₃ -> 2Ag + Zn(NO₃)₂.

Given: 29 g Zn, and 2 g AgNO₃. Molar masses: Zn = 65 g/mol, AgNO₃ = 169.87 g/mol.

Moles Zn = 29/65 = 0.446 mol

Moles AgNO₃ = 2/169.87 = 0.0118 mol

Since the stoichiometric ratio is 1:2 (Zn:AgNO₃), we need 0.223 mol AgNO₃ for a complete reaction.

We have only 0.0118 mol AgNO₃, making it the limiting reagent.

Theoretical yield of Ag: 2 mol Ag produced from 1 mol AgNO₃.

0.0118 mol AgNO₃ * (2 mol Ag / 1 mol AgNO₃) * 108 g/mol (Ag's molar mass) = 2.54 g Ag

The actual yield was 1.329 g Ag.

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The types of chemical bonds present in a material determine the arrangement of atoms or molecules at the microscopic level, which in turn determines the properties of the material at the macroscopic level.

For example, materials with ionic bonds tend to have high melting and boiling points due to the strong electrostatic attraction between positively and negatively charged ions. Covalently bonded materials tend to have lower melting and boiling points due to the weaker intermolecular forces between molecules.

Metallic bonding leads to high electrical and thermal conductivity due to the delocalization of electrons within the metal lattice. These different bond types and resulting material properties are important in understanding the behavior and applications of different materials.

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Answer:

It off soudium and i know this from experments so the answear is b

Explanation:

Answer:

When NH4Cl(s) is added to water, it dissolves and dissociates into its constituent ions NH4+ and Cl-. This is an endothermic process, meaning it requires heat energy to occur. The NH4Cl(s) absorbs heat from the surroundings, including the water in the test tube and the student's hand holding the test tube. As a result, the test tube and the student's hand feel cooler, as some of the heat energy has been transferred to the NH4Cl(s). Therefore, the heat flows from the test tube and the student's hand to the NH4Cl(s).

The correct matches are:

1.A chemical bond between atoms with similar electronegativities - covalent bond

2. a measure of the ability of an atom to attract electrons within a chemical bond - Electronegativity

3. a bond between atoms of greatly differing electronegativities - Ionic bond

4. the bond formed in metals, holding metals together - Metallic bond

A covalent bond is a bond formed by sharing electrons between two atoms that occur in the bond. It generally forms between atoms with similar electronegativity values.

An ionic bond is a bond formed between two oppositely charged ions of her and held by strong electrostatic attraction. It forms between atoms that have vastly different electronegativities.

Electronegativity is the tendency of an atom in a covalent bond to attract a shared pair of electrons.

A metallic bond is a bond formed by electrostatic attraction between a positively charged metal ion and a conduction electron.

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Answer:

Sharing bond: Covalent

Tendency to attract electrons: Electronegativity

Stable electron configurations: Inert gas

Transferred electrons bond: Ionic

The molar enthalpy for the reaction of calcium chloride is -22,982.5 J/mol.

Calcium chloride is a chemical compound that is commonly used as a drying agent due to its hygroscopic properties. In this question, we are given the amount of calcium chloride and asked to determine the molar enthalpy for its reaction with excess potassium.

The given temperature change of the solution in the calorimeter can be used to calculate the heat released or absorbed during the reaction.

To begin, we need to determine the number of moles of calcium chloride in the given amount of 4 g. Using the molar mass of calcium chloride (110.98 g/mol), we can calculate that 4 g of calcium chloride is equal to 0.036 moles. Since the reaction is with excess potassium, we can assume that all the calcium chloride will react.

Next, we can use the heat capacity of the solution and the temperature change to calculate the heat released or absorbed during the reaction. Assuming that the solution is mainly water, we can use the specific heat capacity of water (4.18 J/g°C) to calculate the heat absorbed by the solution.

The mass of the solution is the sum of the mass of calcium chloride and the mass of water, which is 4 g + 7.5 g = 11.5 g. The temperature change is 32 °C - 15 °C = 17 °C. Therefore, the heat absorbed by the solution is:

Q = m x c x ΔT = 11.5 g x 4.18 J/g°C x 17 °C = 827.37 J

Since the reaction is exothermic (heat is released), the molar enthalpy can be calculated using the following equation:

ΔH = -Q/n

where n is the number of moles of calcium chloride. Plugging in the values, we get:

ΔH = -827.37 J/0.036 mol = -22,982.5 J/mol

Therefore, the molar enthalpy for the reaction of calcium chloride is -22,982.5 J/mol.

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The Arrhenius model of acids and bases is limited because it only considers substances that produce hydrogen ions (H⁺) or hydroxide ions (OH⁻) in water as acids or bases, respectively.

Many substances can exhibit acidic or basic properties without producing H⁺ or OH⁻ ions in water. For example, ammonia (NH₃) can act as a base by accepting a proton (H⁺) from an acid, but it does not produce OH⁻ ions in water.

Similarly, substances like aluminum chloride (AlCl₃) can act as an acid by donating a proton (H⁺) to a base, but it does not produce H⁺ ions in water. Therefore, the Arrhenius model fails to explain the acidic or basic properties of such substances that do not fit into the narrow definition of an acid or a base.

This limitation led to the development of other acid-base models like the Bronsted-Lowry model and the Lewis model, which provide a more comprehensive understanding of acid-base behavior.

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The effect of the stratosphere being colder at the bottom than at the top is: no vertical air movement.

The effect of the stratosphere being colder at the bottom than at the top is the separation of gases into layers. This temperature gradient creates a stable atmosphere, which prevents vertical air movement and sudden weather changes.

Additionally, the separation of gases can enhance radio reception, as radio waves are able to travel further and more easily through stable layers of air.

The effect of the stratosphere being colder at the bottom than at the top is: no vertical air movement. This temperature gradient results in a stable atmosphere with limited mixing, preventing significant vertical air movement within the stratosphere.

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The balanced net ionic equation for the given reaction is:

H+ (aq) + OH- (aq) → H₂O (l)

This reaction represents the neutralization of an acid and a base, where the H+ ions from the acid (in this case, H+ from H₃PO₄) react with the OH- ions from the base (in this case, NaOH) to form water (H₂O).

The balanced equation provided in the question involves additional ions, but since those ions are present on both the reactant and product sides of the equation, they do not participate in the net ionic reaction.

The net ionic equation only shows the ions that actually participate in the reaction and undergo a change in oxidation state.

In the given reaction, the calcium ion (Ca₂+) and the phosphate ion (PO₃-) do not undergo any change in oxidation state and remain in their original form in both the reactants and products. Therefore, they cancel out in the net ionic equation.

Overall, the net ionic equation represents a simple acid-base neutralization reaction that results in the formation of water.

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a. The half-life of radon-222 is 3.82 days. b. It will take approximately 11.46 days for the sample to decay to 20% of its original amount.

(a) To find the half-life of radon-222, we can use the formula:

[tex]N = N0 * (1/2)^{(t/T)}[/tex]

where:

[tex]N = amount\ remaining\ after\ time\ t\\N0 = initial\ amount\\T = half\ -life[/tex]

We know that after 3 days, the amount remaining is 58% of the original amount, so N/N0 = 0.58 and t = 3 days. Substituting these values:

[tex]0.58 = (1/2)^(3/T)[/tex]

Taking the natural logarithm of both sides:

[tex]ln(0.58) = ln(1/2)^{(3/T)} \\ln(0.58) = -(3/T) * ln(2)\\T = -(3/ln(2)) * ln(0.58)\\T = 3.82 days[/tex]

(b) To find how long it will take the sample to decay to 20% of its original amount: [tex]N = N0 * (1/2)^{(t/T)}[/tex]

We want to find the time t for which N/N0 = 0.20. Substituting this value and T = 3.82 days into the formula gives:

[tex]0.20 = (1/2)^{(t/3.82)}[/tex]

Taking the natural logarithm of both sides:

[tex]ln(0.20) = (t/3.82) * ln(1/2) \\t = -(3.82/ln(1/2)) * ln(0.20)[/tex]

[tex]t = 11.46 days[/tex]

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11.1384 with 4 significant figures. The answer is rounded to the fourth significant figure because the number given in the equation, 0.1159, contains 4 significant figures.

Figures are visual images or representations used to convey information. They are often used in the sciences, mathematics, engineering, and other technical fields to convey complex data or ideas. Figures can also be used in literature, art, and other creative forms to illustrate stories or themes. Figures can be drawn, photographed, or computer-generated. They are often used to represent statistical information, such as graphs and charts, as well as to illustrate mathematical equations. In the arts, figures can be used to convey a narrative or express an emotion. For example, an artist may use a figure to express the beauty of a landscape or the sorrow of a particular situation. Figures are an effective way to communicate complex concepts and ideas in a concise and visually appealing way.

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The root mean square velocity for N2 gas at 11.8 degrees Celsius is approximately 84.15 m/s.

Here's a step-by-step explanation:

1. Convert the given temperature from Celsius to Kelvin: 11.8 degrees Celsius + 273.15 = 284.95 K.

2. Recall the root mean square velocity (v_rms) formula for a gas:
v_rms = √(3RT/M), where R is the gas constant, T is the temperature in Kelvin, and M is the molar mass of the gas in kg/mol.

3. Identify the molar mass (M) of N2 gas. Nitrogen has an atomic mass of 14.0067, and since it's a diatomic molecule (N2), we have to multiply that by 2: 14.0067 * 2 = 28.0134 g/mol. Convert this to kg/mol: 28.0134 / 1000 = 0.0280134 kg/mol.

4. Substitute the given values into the formula:
v_rms = √(3 * 8.3145 J K^-1 mol^-1 * 284.95 K / 0.0280134 kg/mol).

5. Solve for v_rms:
v_rms = √(3 * 8.3145 * 284.95 / 0.0280134) ≈ √(7082.04098) ≈ 84.15 m/s.

So, the root mean square velocity for N2 gas at 11.8 degrees Celsius is approximately 84.15 m/s.

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The acidity or alkalinity of a solution depends upon its hydronium ion concentration and hydroxide ion concentration. The pH scale is introduced by Sorensen. The pH is 0 when the pOH is 14.

The pH of a solution is defined as the negative logarithm to the base 10 of the value of the hydronium ion concentration in moles per litre.

We have the equation:

pH + pOH = 14

pH = 14 - pOH = 14 - 14 = 0

So the pH is 0.

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Materials that slow down or impede the transmission of heat through them are called insulators. So the correct answer is the option: a.

They can be used for a multitude of purposes, from keeping cold drinks icy to keeping buildings warm in the winter, thanks to this ability. Insulators function by either using materials with low thermal conductivity or by creating air pockets between the materials. This slows the rate of heat flow by reducing the transmission of heat energy from one side to the other. Insulators are valuable in electrical applications because they can stop electrical current from passing through them. Option: a is correct.

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--The complete Question is, These are materials that heat passes slowly or not at all

a. Insulators

b. Fuel

c. Sun

d. Conductors

e. Heat --

Based on the given observations, a chemical change took place when yeast granules were added to hydrogen peroxide.

Observation 1, fizzing and bubbling, is a characteristic sign of a chemical reaction. The bubbles are likely to be the result of a gas, such as oxygen or carbon dioxide, being released during a chemical reaction.

Observation 2, the temperature rise, is also a sign of a chemical reaction. An increase in temperature usually indicates an exothermic reaction, which releases energy in the form of heat.

Therefore, based on these observations, it can be concluded that a chemical change took place when yeast granules were added to hydrogen peroxide.

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The portable hot pack design contains 100g of water and a separated chemical. When mixed, it will achieve a temperature of 55°C (131°F).

The cold pack design also contains 100g of water and a different chemical, reaching 3°C (37°F) when activated.

Hot Pack:
1. Use an exothermic reaction (e.g., calcium chloride dissolving in water).
2. Calculate the heat produced by the chemical reaction using the formula: q = mcΔT.
3. Determine the mass of the chemical needed using stoichiometry.

Cold Pack:
1. Use an endothermic reaction (e.g., ammonium nitrate dissolving in water).
2. Calculate the heat absorbed by the chemical reaction using the formula: q = mcΔT.
3. Determine the mass of the chemical needed using stoichiometry.

For both packs, use a breakable barrier to separate the water and chemical. When the user squeezes the pack, the barrier breaks, allowing the components to mix and initiate the reaction.

In conclusion, our design meets the requirements by using specific chemicals and calculated amounts to achieve the desired temperatures for treating injuries.

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