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

What are the reactants in the reaction? What are their properties? Perform a quick Internet search, if needed.

Answers

The reactants in this reaction are sodium and chlorine. Sodium is a soft, silvery-white metal that is highly reactive. Chlorine is a poisonous greenish-yellow gas that has an odor and combines readily with other elements.

This might be the exact question so you might wanna rephrase it but good luck! :)))

A reactant is a substance that undergoes change during a chemical reaction.

A reaction in a chemical experiment is which takes place when there are mixtures between two or more reactants.

There are about four types of reactions which are:

SynthesisDecompositionSingle replacementDouble replacement

Please note that your question is not complete, therefore, i would give you a general overview to help you.

Some examples of reactants include:

HydrogenSodiumChlorine, etc

Read more here:

https://brainly.com/question/12056938

How are clouds formed? Simple answer please!

Answers

Answer:

Clouds form when the invisible water vapor in the air condenses into visible water droplets or ice crystals. For this to happen, the parcel of air must be saturated, i.e. unable to hold all the water it contains in vapor form, so it starts to condense into a liquid or solid form.

Explanation:

MARK ME BRAINLIEST!!!!!!!! THANKS BESTFRIENNNNNDDDDD!!!!!!!!

Answer:

Clouds form when the invisible water vapor in the air condenses into visible water droplets or ice crystals. For this to happen, the parcel of air must be saturated, i.e. unable to hold all the water it contains in vapor form, so it starts to condense into a liquid or solid form.

Explanation:

I HOPE THIS HELPS*--- *meow*

help me please with my science test questions 5 and 6​

Answers

Answer:

5. Element J has the highest atomic number

6. Elements G and L have the same number of electrons in their outermost shell.

Explanation:

The periodic table of elements is a table which shows the arrangement of the elements in the order of increasing atomic number. Starting from the topmost left-hand side of the table where the element with the least atomic number is placed, and going across the table from left to right and down to the lowest point to the right of the table, where the element with the highest atomic number is located, the atomic number of elements progressively increases.

Looking at the table, it can be seen that the element J is found at the lowest point to the right of the table. Therefore, element J has the highest atomic atomic number.

6. In the periodic table, elements are arranged into groups and periods. The groups are the columns while the periods are the rows. Elements in the same column or group have the same number of electrons in their outermost shell. Therefore, element G and L have the same number of electrons in their outermost shell.

Question 2
1 pts
What is the molar mass of Cr2(SO4)3?
O 148.1 g
0 288.0 g
O 344.2 g
0 392.2 g
200.0 g

Answers

Answer:

392g

Explanation:

The given compound is;

         Cr₂(SO₄)₃

To find the molar mass, we sum the atomic masses of the elements in the compounds together.

Atomic mass of Cr  = 52

                           S  = 32

                            O  = 16

So;

 Molar mass  = 2(52) + 3[32 + 4(16)]  = 392g/mol

Stephanie the Skydiver has a mass of 48kg, what is the force that she
exerts as she is falling to the ground?

Answers

Answer:

470.4N

Explanation:

Given parameters:

Mass of Stephanie  = 48kg

Unknown:

Force she exerts while falling to the ground  = ?

Solution:

The force she exerts is her weight;

  Weight  = mass x acceleration due to gravity

  Now insert the parameters ands solve ;

  Weight  = 48 x 9.8 = 470.4N

How many carbon atoms are represented by the model below?

Answers

Answer:

3

Explanation:

In the model it shows 3 carbon atoms, the person above me is correct

jupiter is much more larger than earth , would gravity be weaker or stronger here?

Answers

Answer:

stronger

Explanation:

there is more gravity on Jupiter since it is bigger than earth

A sample of pure radioactive isotope is left to decay. After 40.0 days, the 1 point
sample is placed in a mass spectrometer, and it is determined that only
25% of the original isotope remains. How long is the half-life?

Answers

Answer:

6 months and 1 day

Explanation:

Need a little help with science please

Answers

Answer:

I'm pretty sure its liver and pancreas

Explanation:

the pancreas delivers the digestive juice to the small intestine through small tubes, your liver makes the digestive juices called the bile that helps digest fats and some vitamins

Answer:

the answer is liver and pancreas

A vector is a quantity with magnitude and ____

Answers

A direction . A vector quantity.

Answer:

direction

Explanation:

A P E X

Magnetic Field
What is a magnetic field?

Answers

Answer:

a region around a magnetic material or a moving electric charge within which the force of magnetism acts. hope it helps :)

Answer:

is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials

Explanation:

A sample of He has volume of 4.40 L at 555 torr and 33.0 C. Find the new pressure if the volume decreases to 3.50 L and the temperature increases to 44.0 C.
723 torr
504 torr
800. torr
612 torr

Answers

Answer:

723 torr

Explanation:

Using the formula;

P1V1/T1 = P2V2/T2

Where;

P1 = initial pressure (torr)

V1 = initial volume (Litres)

T1 = initial temperature (°C)

P2 = final pressure (torr)

V2 = final volume (L)

T2 = final temperature (°C)

Based on the information provided in this question, V1 = 4.40L, P1 = 555 torr, T1 = 33.0 °C + 273 = 306K, V2 = 3.50 L, P2 = ?, T2 = 44.0 °C + 273 = 317K.

Using the formula above:

555 × 4.4/306 = P2 × 3.5/317

2442/306 = 3.5P2/317

Cross multiply;

2442 × 317 = 306 × 3.5P2

774114 = 1071 P2

P2 = 774114 ÷ 1071

P2 = 722.79

P2 = 723 Torr

Please help quick
1) How much heat does 23.0 g of water absorb as its temperature increases from 25.4 °C to 42.8 °C?

2) A sample of unknown metal has a mass of 120.7 g. As the sample cools from 90.5 °C to 25.7 °C, it releases 7020 J of energy. What is the specific heat of the sample?

Answers

Answer:

c = 0.898 J/g.°C

Explanation:

1) Given data:

Mass of water = 23.0 g

Initial temperature = 25.4°C

Final temperature = 42.8° C

Heat absorbed = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Specific heat capacity of water is 4.18 J/g°C

ΔT = 42.8°C - 25.4°C

ΔT = 17.4°C

Q = 23.0 g ×  × 4.18 J/g°C × 17.4°C

Q = 1672.84 j

2) Given data:

Mass of metal = 120.7 g

Initial temperature = 90.5°C

Final temperature = 25.7 ° C

Heat released = 7020 J

Specific heat capacity of metal = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = 25.7°C - 90.5°C

ΔT = -64.8°C

7020 J = 120.7 g ×  c ×  -64.8°C

7020 J = -7821.36 g.°C ×  c

c = 7020 J / -7821.36 g.°C

c = 0.898 J/g.°C

Negative sign shows heat is released.

Hydrogen bonds are in the family of Van der Waals forces. They are weaker than ionic and covalent bonds but they cause interesting changes with different chemicals.

What is one of the changes that hydrogen bonds are responsible for?

A. Cause DNA has the double helix shape.

B. Causes salts quickly dissolve in water.

C. Cause sugar looks like a crystal.

D. Cause liquid H2O to have a larger volume than frozen (solid) H2O

Answers

Answer:

The answer is B. Van der Waals forces are weaker than ionic and covalent bonds.

Explanation:

In general, if we arrange these molecular forces from the strongest to weakest, it would be like this:

Covalent bonds > Ionic bonds > Hydrogen bonds > Dipole-Dipole Interactions > Van der Waals forces

Covalent bonds are known to have the strongest and most stable bonds since they go deep and into the inter-molecular state. A diamond is an example of a compound with this characteristic bond.

Ionic bonds are the next strongest molecular bond following covalent bonds. This is due to the protons and electrons causing an electro-static force which results to the strong bonds. An example would be Sodium Chloride (NaCl), which when separated is Na⁺ and Cl⁻.

Van der Waals forces, also known as Dispersion forces, are the weakest type of molecular bonds. They are only formed through residual molecular attractions when molecules pass by each other. It doesn't even last long due to the uneven electron dispersion. It can be made stronger by adding more electrons in the molecule. This kind of molecular bonds appear in non-polar molecules such as carbon dioxide.

HOPE THIS HELPS!!!!!!!!!!!!!!

///////////////////////////////////////////////////////////////////////////////////////////

The change that Hydrogen Bonds are most likely responsible for would be:

B). Causes salts to quickly dissolve in water.

As per the details provided, the hydrogen bonds are classified into the category of Van der Waals forces and the primary reason behind this has been that it leads salt to solvate immediately in the water. Amongst all the bonds, covalent bonds are characterized as the toughest while ionic bonds and hydrogen bonds are followed by it in terms of strength.The reason for which hydrogen bonds cause the change of allowing salts to dissolve immediately is that it illustrates a weaker strength of molecules due to its formation with residual uneven construction.

Thus, option B is the correct answer.

Learn more about 'Covalent Bonds' here:

brainly.com/question/10777799

can someone help me (╥︣﹏᷅╥)


Water stored in snow and ice can return directly to the atmosphere through the process of sublimation.

((its timed pLEasE


Please select the best answer from the choices provided


T

F

Answers

I believe the answer is true:)
i think it’s true!! not sure

I will give brainliest to whoever is first ❗️❕❗️❕❗️❕❗️
Which diagram best represents the reflection of the light from an irregular surface

Answers

3rd Answer. Rays reflect in random directions
C.Light that bounces off a smooth surface bounces down and back up.

But, an irregular surface, for every bump, the light bounces down up down up down up.

In conclusion, C is the best answer.

I hope this helped! +*♡

SOMEONE HELP PLS ILL GIVE BRAINLIEST AND 19 PT

Answers

Sample left = 6.25 g

The percentage = 6.25%

Further explanation

Given

t1/2 = half-life = 3.8 days

t = decay time = 15.2 days

No = initial sample = 100 g

Required

Nt = final sample left

The percentage

Solution

General formulas used in decay:  

[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]

Input the value :

[tex]\tt N_t=100.\dfrac{1}{2}^{15.2/3.8}\\\\N_t=100.\dfrac{1}{2}^4\\\\N_t=6.25~g[/tex]

The percentage : Nt/No

6.25 : 100 = 6.25%

What do all volcanos emit?

Answers

Answer:

By far the most abundant volcanic gas is water vapor, which is harmless. However, significant amounts of carbon dioxide, sulfur dioxide, hydrogen sulfide and hydrogen halides can also be emitted from volcanoes.

Many human activities result in carbon dioxide emissions.
Our carbon footprint is a measure of how much carbon dioxide we each cause to be produced.
(a) Why should we be concerned about our carbon footprint?
(b) Most power stations in the UK burn coal.
Coal was formed from tree-like plants over millions of years.
Suggest why burning wood instead of coal would help to reduce our carbon footprint.

Answers

Answer:

: the average human-driven CO2 emissions per year climbed 1.4%

every household makes about 7 tons worth of Co2

A C02 footprints are produced at such high rates and hurts plants and the environment

B coal is a very inexpensive and efficient way to generate electricity. Since its a large quantity of them which still produces alot co2  unlike wood, burning wood doesn't  produce as much but it's much harder to ignite and get to last because it takes coal almost 100 degrees and wood takes about 700 degrees

i dont know the answer pls help me​

Answers

Answer:

Unicellular

Explanation:

Unicellular organisms are made up of only a single cell

D. The ¬_____________________ converts food into energy. It is found in both plant cells and animal cells.

Answers

Answer:

I believe it’s the mitochondria

Explanation:

Answer:

Mitochondria

Explanation:

Ik bc i have the vocab for that question

Need help with this question please I’m really really going to appreciate it

Answers

Answer:

Alpha

Explanation:

^4 _2 He = alpha

^0 _-1 b = beta

^0 _0 y = gamma

what is a displacement reactions​

Answers

Displacement Reaction:

A displacement reaction is the one wherein the atom or a set of atoms is displaced by another atom in a molecule. For instance, when iron is added to a copper sulphate solution, it displaces the copper metal.

A + BC → AC + B

The above equation exists when A is more reactive than B.

A and B have to be either:

Halogens where C indicates a cation.

Different metals wherein C indicates an anion.

Question:-

[tex]\textsf{what is a displacement reactions?   }[/tex]      

Answer:

[tex]\large \underbrace{ \underline{ \sf Displacement \: reaction}}[/tex]

The reaction in which more reactive element replace a less reactive element from its compound is called displacement reaction.

Ex:-

[tex]\bold{\large Zn+HCl \longrightarrow ZnCl_2+H_2}[/tex]

Which best describes what is represented by images 1 and 2?

Image 1 shows a polymer, and Image 2 shows a monomer.
Image 1 shows a monomer, and Image 2 shows a polymer.
Image 1 shows a macromolecule, and Image 2 shows a synthetic polymer.
Image 1 shows a synthetic polymer, and Image 2 shows a macromolecule.

Answers

Answer:

b

Explanation:

im doing a test about it

Answer:

b

Explanation:

Please help me this is my science final

Answers

Answer:

1.Winter

2.Autmn

3.Summer

4.Spring

I hope this helps!

1- winter
2- autumn
3- summer
4- spring

Give an example of a chemical reaction during which a single substance breaks
down. *

Answers

Answer:

2NaCl(l) => 2Na(s) + Cl₂(g)

Explanation:

Electrolysis of melt NaCl to form sodium (Na) metal and chlorine (Cl₂) gas.

This is a class of reaction called 'Decomposition Rxns'. For what it's worth, there are 6 distinct compound types that undergo breakdown by decomposition. The acronym C O A C H E can help remember them.

C - Carbonates => CaCO₃(s) => CaO + CO₂

O - Oxides of Metals => 2Fe₂O₃(s) => 4Fe°(s) + 3O₂(g)

A - Acids (Oxoacids) => H₂CO₃(aq) => CO₂(g) + H₂O(l)

C - Chlorates, Bromates & Iodates => 2KClO₃(s) => 2KCl(s) + 3O₂(g)

H - Hydroxides => Ca(OH)₂(s) => CaO(s) + H₂O(l)

E - Electrolysis => see above electrolysis of NaCl(l)

Answer:

2NaCl(l) => 2Na(s) + Cl₂(g)

Explanation:

Which ones are elements, compounds I’ll give brainliest.

Answers

Calcium Copper(Cu),Oxygen(02)

What is a lone pair?
A. Two pairs of electrons that form a double bond
B. Two atoms that have been pushed close to each other
C. A pair of electrons that is not used in bonding
D. A diatomic molecule attracted to no other molecule

Answers

Answer:

I BELIEVE IT is c.

Explanation:

please help!! I’m really confused because it’s actually supposed to be called occluded front but the definition is true.

Answers

I believe it is False

What is the correct number of digits to express a measurement

Answers

Answer:

Examples of measured numbers: The diameter of a coin, such as 10.2 mm. The weight of an object, such as 8.887 grams. The length of a pen, such as 12 cm.

Explanation:

Answer:

It completely depends on what you are measuring, what instrument you are using, and the uncertainty associated with your measurement.

Explanation:

When expressing a measurement, there is always going to be a part that you know, and a part that you guess. They both make up known numbers collectively called significant figures (commonly shortened to "sig figs"). For instance, imagine you are measuring the length of a pencil. Let's say it is a typical ruler with divisions of 0.1 cm (picture for reference). You measure the pencil, and to your eyes it looks like it is about 9 cm and 5 small tick marks (so, 0.5 cm), so we'll call that 9.5 cm. Now, this is a known value, so you are certain that it is a least 9.5 cm. However, it may be true that there is one more decimal place that can be known. The general rule is that you want to add one more uncertain digit to the rightmost side of the number, and how many digits depends on the divisions of the instrument. Our ruler has divisions of 0.1 cm (the small tick marks), and so we will go one more place out, and add another digit. Now, let's say our eyes are pretty good, so let's say it's 9.5 cm, and then add that one uncertain digit, a 0 to the smallest division of 0.1, so, 0.10. The final measurement we record is 9.50 cm. Now, it may seem like we are simply guessing or even being unreasonable in our assessment of how long this pencil is. I can promise you that not knowing the actual measurement of this pencil will not make a spaceship crash because of a specification that was not the "right measurement". For those life-or-death measurements, much more precise measurement machines are used; this is just a pencil. Also, it would be unreasonable to say that it is 9.500000 cm or 9.500001 cm. We do not have that kind of certainty with this ruler, only divisions of 0.1 cm, so we can only estimate out to one more decimal place.

In short, find the smallest division of a ruler or whatever device (like a chemical beaker) you are using, and then add one uncertain digit to the end of that. If it's 0.1 cm, then add one digit to that. (example: 5.6 --> 5.63; 3 because that is what it looks like on the ruler). If it's 1 cm, then add an extra .1, so the measurement is 1.1 cm. And of course, it's not always cm you are using, that was just an example. Best of luck!

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