How can you ensure the chemical reaction produces the right amount of heat in a hot pack without hurting you?

Answers

Answer 1

Answer:

Heat packs that contain iron and water packets: Exposing the solution to air results in the oxidation of the iron (creates rust). The oxidation of the iron is an exothermic process. Heat packs that contain supersaturated sodium acetate: These are reusable, the packs are boiled to dissolve sodium acetate.

Explanation:Thanks for asking question


Related Questions

How many grams are in 3.00 x 10^24 molecules of Zn(C2H3O2)2?​

Answers

Answer:

Mass = 917.4 g

Explanation:

Given data:

Number of molecules = 3.00 ×10²⁴ molecules

Mass in gram = ?

Solution:

1 mole contain 6.022 × 10²³ molecules

3.00 ×10²⁴ molecules × 1 mol /  6.022 × 10²³ molecules

0.5×10¹ mol

5 mol

Mass in gram:

Mass = number of moles  × molar mass

Mass = 5 mol  × 183.48 g/mol

Mass = 917.4 g

is reacts with acid a chemical or physical property? (WORTH 30 Points.)

Answers

Answer:

Metals in general have they chemical property of reacting with an acid. Zinc reacts with hydrochloric acid to produce hydrogen gas. This is a chemical property. Chemical change results in one or more substances of entirely different composition from the original substances.

Metal reacts with acid is a chemical property.

Metals react with acids which causes the production of salt and hydrogen gas is released. This is a chemical property because the reactions of reactant produces new type of products which is totally change from the parent material or reactants. The  chemical property is refers to change of one type of matter into another type so we can conclude that reaction of metals with acid is a chemical property.

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can we seperate naphthalene from sugar by filtration to obtain pure sugar?​

Answers

Yes, distillation is the process by which sugar can be separated from the sugar solution.

Answer:

As Naphthalene undergoes sublimation, we use sublimation process. On condensing naphthalene can be separated.

Calculate the molar mass of NaNO3-

Answers

The molar mass is 37 grams



How does the number of molecules in 1 mol of oxygen compare with the number of molecules in 1 mol of nitrogen?
1 mol of oxygen has fewer molecules.
1 mol of oxygen has more molecules.
Each sample has the same number of molecules.
The molecules cannot be compared without knowing the mass.


Answers

Answer:

Each sample has the same number of molecules.

Explanation:

Just took the quiz on edge 2021

Taking into account the definition of Avogadro's number, each sample has the same number of molecules.

Avogadro's Number

Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole.

Avogadro's number applies to any substance.

This case

Avogadro's number applies to any substance. This means that the number of molecules in 1 mol of oxygen is equal to the number of molecules in 1 mol of nitrogen.

Finally, the correct answer is the third option: each sample has the same number of molecules.

Learn more about Avogadro's Number:

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How many different methods can you list for how we generate electricity in this country. Which of those methods do we use the most, and which of them should we invest more in

Answers

Answer:

1. Broadly, there are three different methods for how electricity is generated in the United States. They include; Fossil fuels, Nuclear energy, and Renewable energy sources.

2. Fossil fuels, are used the most, with Natural gas topping the list by 38%.

3. More should be invested into renewable gas. It is a clean source of energy and investing in it would bring about a cleaner and safer environment.

Explanation:

Fossil fuels arise from plants and animals that have been long dead and can can now be converted to sources of energy. Examples include; coal natural gas, crude oil. etc.  

Nuclear energy arises from the fission of uranium atoms, nuclear decay, and nuclear fusion. They are safe since green house gases are not emitted. Thermal energy can be generated as the byproduct of these reactions.

Renewable sources of energy are generated from natural sources which are always available. Examples are; sun, wind, biomass, water, and geothermal sources,

Suppose that 3.33 g of acetone at 25.0 °C condenses on the surface of a 44.0-g block of aluminum that is initially at 25 °C. If the heat released during condensation goes only toward heating the metal, what is the final temperature (in °C) of the metal block?

Answers

Answer:

68.6 °C

Explanation:

From conservation of energy, the heat lost by acetone, Q = heat gained by aluminum, Q'

Q = Q'

Q = mL where Q = latent heat of vaporization of acetone, m = mass of acetone = 3.33 g and L = specific latent heat of vaporization of acetone = 518 J/g

Q' = m'c(θ₂ - θ₁) where m' = mass of aluminum = 44.0 g, c = specific heat capacity of aluminum = 0.9 J/g°C, θ₁ = initial temperature of aluminum = 25°C and θ₂ = final temperature of aluminum = unknown

So, mL = m'c(θ₂ - θ₁)

θ₂ - θ₁ = mL/m'c

θ₂ = mL/m'c + θ₁

substituting the values of the variables into the equation, we have

θ₂ = 3.33 g × 518 J/g/(44.0 g × 0.9 J/g°C) + 25 °C

θ₂ = 1724.94 J/(39.6 J/°C) + 25 °C

θ₂ = 43.56 °C + 25 °C

θ₂ = 68.56 °C

θ₂ ≅ 68.6 °C

So, the final temperature (in °C) of the metal block is 68.6 °C.

The final temperature of the metal block is 74.97°C

What is the specific heat?

The specific heat of a substance is the required quantity of heat needed to raise the temperature of 1 gram of the substance by 1° C.

From the parameters given:

The mass of acetone = 3.33 g

The number of moles of acetone is:

[tex]\mathbf{= 3.33 g \times \dfrac{mol}{58.08 \ mol}}[/tex]

= 0.0573 mol

At standard conditions, the heat of vaporization of acetone is:

[tex]\mathbf{\Delta H = 32.0 \ kJ/mol \times 0.0578 \ mol } \\ \\ \mathbf{\Delta H = 1.8496 \ kJ } \\ \\ \mathbf{ \Delta H = 1.85 \times 10^3 \ J}[/tex]

Given that:

The mass of the metal (m) = 44.0 gThe initial temperature [tex]\mathbf{T_1}[/tex] = 25° CThe final temperature [tex]\mathbf{T_2 = ???}[/tex]

The specific heat of the aluminum is = 0.903 J/g° C

The heat energy can be computed as:

q = msΔT

q = 41 g × 0.903 J/g° C × (x - 25°C)

Using the calorimetry principle, heat energy lost by metal = heat energy gained by acetone.

i.e.

[tex]\mathbf{q_{(acetone)} gain = q_{(metal)} lost }[/tex]

[tex]\mathbf{-1.85 \times 10^3 \ J = - 41 g \times 0.903 \ J/g^0 C \times ( x - 25^0 c) }[/tex]

[tex]\mathbf{1.85 \times 10^3 \ J = 41 g \times 0.903 \ J/g^0 C \times ( x - 25^0 c) }[/tex]

[tex]\mathbf{(x - 25 ^0 C) = \dfrac{1.85 \times 10^3 \ J }{ 41 g \times 0.903 \ J/g^0 C}}[/tex]

[tex]\mathbf{(x - 25 ^0 C) = 49.97^0 C}}[/tex]

[tex]\mathbf{x = 49.97^0 C+25 ^0 C}}[/tex]

x = 74.97 °C

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1.004 mol Arsenic is how many atoms?

Answers

Answer:  [tex]6.047\times 10^{23}[/tex] atoms in 1.004 mol of arsenic

Explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.

To calculate the atoms, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given atoms}}{\text {avogadro's number}}[/tex]

[tex]1.004=\frac{x}{6.023\times 10^{23}}[/tex]

[tex]x=1.004\times 6.023\times 10^{23}=6.047\times 10^{23}[/tex]

Thus there are [tex]6.047\times 10^{23}[/tex] atoms in 1.004 mol of arsenic

Which is a property of potassium (K)?
A. It is dull and brittle.
B. It is extremely reactive.
C. It is not reactive.
D. It is white and hard.

Answers

Answer:

B: It is extremely reactive

Explanation:

Potassium metal is also soft and white with a silvery lustre, has a low melting point, and is a good conductor of heat and electricity.

Answer: Properties, occurrence, and uses. Potassium metal is soft and white with a silvery lustre, has a low melting point, and is a good conductor of heat and electricity. Potassium imparts a lavender colour to a flame, and its vapour is green.

Explanation: hope it helps

The magnifying power of a telescope is computed by dividing the focal length of its objective by _______.

Answers

Answer:

by focal length of the eyepiece.

Explanation:

hope it helps!!plz mark as brainleist.

A certain atom has 50 protons and 69 neutrons. Which statement(s) below are true about this atom? Choose ALL that apply.
this atom is an atom of thulium (Tm)
m this atom has a mass of 69 amu
this atom is an isotope of tin-120
m this atom has an atomic number of 50

Answers

Answer:

D.) This atom has an atomic number of 50

Explanation:

A is wrong because we determine the type of atom by their number of protons, not the number of neutrons. This makes the atom Tin (Sn).

B is wrong because both protons and neutrons contribute to the weight of an atom, not just neutrons

C is wrong because the correct name for this isotope would be tin-119, which is calculated by adding the protons and neutrons

D is correct because isotopes of the same element always share the same atomic number

Covalent bonds can be single, double, or triple.

How many electrons are shared in a molecule, like O2 that has a double bond?

4

6

12

2

Answers

Im pretty sure the answer would be 2. Bc that’s how many is shared between O2

PLS HELP THIS IS DUE TODAY!!

Answers

Answer:

I think it would be Yellow

If you were to descend through the ocean in a submersible, what changes in the ocean water could you observe?

Answers

Answer:

it would become darker. there would be a higher level of water pressure. and there would be less animals, or different alimals.

What is it that lives if it is fed, and dies if you give it a drink

Answers

Answer:

fire

Explanation:

Answer:

ants if you splash a ant with sum water that shít is dead

___co+__ Na2s--> ___ Na+ ___ cos2

Answers

Answer: [tex]Co+2Na_2S\rightarrow 4Na+CoS_2[/tex]

Explanation:

According to law of conservation of mass, mass can neither be created nor be destroyed. The atoms on the reactant side must be equal to the number of atoms on the product side so that the mass remains the same on reactant and product side. Thus the reactions are balanced.

Single displacement reaction is one where a more reactive element replaces the lesser reactive one.

The balanced chemical reaction will be:

[tex]Co+2Na_2S\rightarrow 4Na+CoS_2[/tex]

What is the product(s) of the reaction below?
2Al(s) + Fe2O3(s) ---> Al2O3(s) + 2Fe(s)
A. Solid aluminum oxide and solid iron
B. Solid aluminum
C. Saturated aluminum oxide and saturated iron
D. Iron(III) oxide and aluminum oxide

Answers

Answer:

A. Solid aluminum oxide and solid iron

Explanation:

The reaction equation is given as:

    2Al  +   Fe₂O₃  →   Al₂O₃   + 2Fe

The species on the left hand side are the reactants

Those on the right hand side of the expression are the products.

The products are:

Al₂O₃   and Fe

 These are solid aluminum oxide and solid iron

This chemical equation represents a chemical reaction H2SO4 + 2LiOH Li2SO4 + 2H2O which two chemicals are the products of the chemical reaction shown?

Answers

Answer:

Lithium sulphate (Li₂SO₄) and water (H₂O

Explanation:

H₂SO₄ + 2LiOH —> Li₂SO₄ + 2H₂O

The equation represented above indicates a neutralization reaction.

A neutralization reaction is a reaction involving acid and base which result in the production of salt and water.

In the equation above,

Reactant:

H₂SO₄ (acid)

LiOH (base)

Product:

Li₂SO₄ (salt)

H₂O (water)

Thus, lithium sulphate (Li₂SO₄) and water (H₂O) are the products of the reaction

a sample of methane gas at a pressure of 0.727 atm and a temperature of 26.9 occupies a volume of 726 ml. if the gas is allowed to expand at constant temperature until its pressure is 0.412 atm, the volume of the gas sample will be _ mL

Answers

Answer:

1280L

Explanation:

Given parameters:

Initial pressure  = 0.727atm

Temperature  = 26.9°C

Initial volume  = 726mL  = 0.726L

New pressure  = 0.412atm

Unknown:

New volume of the gas sample  = ?

Solution:

To solve this problem, we apply boyles law;

            P1V1  = P2V2

P and V are pressure and temperature

1 and 2 are initial and new state

             0.727 x 0.726  = 0.412 x V2

                   V2  = 1.28mL  = 1280L

. The kidneys are _______________ to the liver.
a. Dorsal
b. Ventral
c. Medial
d. Superior

Answers

I’d say posterior because the right kidney is slightly above where the liver is

Can someone answer ASAP if you hurry I will mark brainliest

Answers

Answer:

Electrical and magnetic

You exert a gravitational force on the pupil and the pupil exerts an equal gravitational force on you. ... The size of the gravitational force depends on the mass of the objects involved. The greater the mass, the greater the gravitational force.

Explanation:

how many element are there on the periodic table?

Answers

Answer:118

Explanation: it’s right

Answer:

118 elements

Hope that helps

Write the name for the IONIC compound that contains two aluminum atoms and three sulfur atoms. (Need help ASAP)

Answers

Ionic compound
Al +3 charge, Aluminum
S -2 charge, Sulfur

Al2S3

Explain why the answer is correct and why the others aren’t.
Pleaseeee

Answers

Answer:

Buffalo and Watertown.

Explanation:

This is correct as the Interior lowlands are located ib the US. These are correct as the others are in the US but aren't located anywhere near the Interior Lowlands.

Please help me
There are many different renewable resources available in Florida. Which of the following can be described as a renewable resource?

Answers

Wind energy is a renewable resource

If the [H+] of a solution is 6.8 x 10-9 mol/L the pH is

Answers

Answer:

8.2

Explanation:

To solve this problem;

 The concentration of [H⁺]   = 6.8 x 10⁻⁹mol/L

So, we need to convert this to pH:

           pH  = -log [H⁺]

So;

          pH  = -log 6.8 x 10⁻⁹ = 8.2

Brianna explains to Logan the role of plants in the carbon cycle. Choose the sentence(s) that she includes in her explanation. Select all that apply.
A.

Animals get carbon from plants.
B.

Plants take carbon from the soil.
C.

Photosynthesis uses carbon monoxide.
D.

Animals take carbon from the atmosphere.
E.

Plants take carbon from the atmosphere.

Answers

Answer:

E) Plants take carbon from the atmosphere

Explanation:

Plants are a vital part in keeping the air clean. They take in CO2, H2O, and sunlight to start processing photosynthesis. The carbon taken in by the plant still remains with it after it dies, thus, fossil fuels.  

Answer:

e is correct

Explanation:

An atom of chlorine with a mass number of 37 contains __ protons and __ neutrons.

Answers

Answer:

Its in the Explanation

Explanation:

Here's what I got.

Aluminium-27 is an isotope of aluminium characterized by the fact that is has a mass number equal to  

27

.

Now, an atom's mass number tells you the total number of protons and of neutrons that atom has in its nucleus. Since you're dealing with an isotope of aluminum, it follows that this atom must have the exact same number of protons in its nucleus.

The number of protons an atom has in its nucleus is given by the atomic number. A quick looks in the periodic table will show that aluminum has an atomic number equal to  

13

.

This means that any atom that is an isotope of aluminum will have  

13

protons in its nucleus.

Since you're dealing with a neutral atom, the number of electrons that surround the nucleus must be equal to the number of protons found in the nucleus.

Therefore, the aluminium-27 isotope will have  

13

electrons surrounding its nucleus.

Finally, use the known mass number to determine how many neutrons you have

mass number

=

no. of protons

+

no. of neutrons

no. of neutrons = 27 − 13 = 14

Your welcome :)

In _____ , materials move from an area of higher concentration to an area of lower concentration through a cell membrane.
1.selective permeability
2.active transport
3.passive transport

Answers

Answer = 1.selective permeability

how can balancing equations support the law of conservation

Answers

Answer:

detail is given below.

Explanation:

This law was given by French chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

For example:

In given photosynthesis reaction:

6CO₂ + 6H₂O  → C₆H₁₂O₆ + 6O₂

The given equation is balanced chemical equation of photosynthesis. There are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass.

If equation is not balanced,

CO₂ + H₂O  → C₆H₁₂O₆ + O₂

It can not follow the law of conservation of mass because mass is not equal on both side of equation.

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