What mass of solute will dissolve in 100g of water at the following temperatures?
• KNO3 at 70°C =
• NaCl at 100°C=
• NH₂Cl at 90°C=

The best explanation for why a firework being ignited is an example of an exothermic reaction and not an endothermic reaction is:

The fireworks give off heat.

Heat is emitted into the environment in an exothermic reaction. When a firework is lit, it undergoes a number of chemical processes inside the firework combination, which produces gases and produces a great deal of heat. Fireworks' distinctive visual display and audible effects are produced when heat is released as light and sound.

In contrast, heat is taken from the environment during an endothermic reaction. If a reaction were endothermic, it would need an outside energy source to continue, and because it would be absorbing heat from its environment, it would feel chilly to the touch.

However, because they release heat and energy and brighten the night sky, fireworks are instances of exothermic reactions.

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Answer:

2.17 gm Al

Explanation:

First, find the number of moles .   Then multiply by the mole weight of aluminum.

# moles =   4.85 x 10^22 / 6.022 x 10^23 = .08053 moles

.0805 moles * 26.981 gm/mole  = 2.173 gm

Answer: when a reaction absorbs heat or decreases the entropy of the system,

Explanation: :)

Answer:

1-bromo-6-chloro-5-methylheptane

Explanation:

There are 3 substituents, 1 chlorine, 1 bromine, and 1 methyl group.

The longest carbon chain consists of 7 carbons.

There are no double bonds, based on the saturation and substituents.

So you have a 1-bromo-6-chloro-5-methylheptane.

Hope that was the brainliest answer!

The work function of the metal is obtained as 5.1 eV

The cutoff frequency is the frequency below which photo electric effect can not occur as electrons are not removed from the metal surface.

Now;

fo = 1.22 x 10^15 Hz

Wo = hfo

Wo = 6.6 * 10^-34 * 1.22 x 10^15

Wo = 8.1 * 10^-19 J

If 1 eV = 1.60 x 10-19 J

x eV = 8.1 * 10^-19 J

x = 8.1 * 10^-19/ 1.60 x 10-19

x = 5.1 eV

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Answer:

See below

Explanation:

Simply :    2.357 g / 75 ml = .03142  gm/ml   or  31.42  gm / liter

a) Alpha decay occurs when an unstable nuclide emits an alpha particle, (which is just a helium-4 atom), which contains 2 protons and 4 neutrons. This means that transmutation has occurred (since a nuclide of a different element will be produced), and this newly produced nuclide will have 2 fewer protons and 4 fewer neutrons than the original nuclide.

b) [tex]^{234}_{92} \text{U} \longrightarrow ^{4}_{2} \text{He}+^{230}_{90} \text{Th}[/tex]

c) Alpha decay occurs when an unstable nuclide emits a beta particle, (also known as an electron). This causes transmutation (since a nuclide of a different element will be produced), and this newly produced nuclide will have 1 more proton than the original nuclide.

d) [tex]^{131}_{53} \text{I} \longrightarrow ^{0}_{-1} \beta+^{131}_{54} \text{Xe}[/tex]

Answer:

An exergonic reaction releases free energy, and an endergonic reaction absorbs free energy.

Explanation:

hope it helps

Answer:

1.3 x 10²⁴ atoms Fe

Explanation:

To convert moles to atoms, you need to multiply your given value by Avogadro's Number. This causes the conversion to occur because Avogadro's Number exists as a ratio. It is the ratio that allows for the cancellation of units during multiplication. This is why atoms should be in the numerator of your conversion. The final answer should have 2 sig figs to reflect the given value.

Avogadro's Number:

1 mole = 6.022 x 10²³ atoms

2.1 moles Fe          6.022 x 10²³ atoms
---------------------  x  -------------------------------  =  1.3 x 10²⁴ atoms Fe
                                        1 mole

The activity series of metals as well as the electrode potential of metals can be used to compare the reactivity of metals.

The reactivity of metals can be compared using their electrode potentials which is a measures of the ability of the metal to donate electrons to another metal.

When comparing the reactivity of metals, the metal with the lesser negative electrode potential will be more reactive than another with a greater negative or positive electrode potential.

Therefore, the activity series of metals as well as the electrode potential of metals can be used to compare the reactivity of metals.

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Answer:

i think the answer is Continental polar air masses

Explanation:

Answer:

'An ion has a non-zero electric charge. A radical has an atom with unfilled electron shells and so is very reactive, but is electrically neutral.'

'Atoms are single neutral particles. Molecules are neutral particles made of two or more atoms bonded together.'

'The primary difference that lies between these organic compounds and inorganic compounds is that organic compounds always have a carbon atom while most of the inorganic compounds do not contain the carbon atom in them.'

Organic and inorganic compounds:

Similarities:::---

1) In both organic and inorganic compound, the elements joining in making compound complete their octet.

2) Organic compound shows isomerism (R/S , E/Z , cis/trans, enantiomers, diastereomers, etc), just as inorganic compound do (Δ/Λ, enantiomers, R/S enantiomers, cis/trans, fac/mer isomers, etc).

3) Organic compound and inorganic compounds can be very active in chemical reactions, e.g. organolithium reagents could be flammable or even pyrophoric (generally stored under 10°C), while inorganic reagents like in this paper are quite rapid...

Differences:::---

1) Organic compound are very long in size so they can make polymer but inorganic compound are not very long but its structure might me complex.

2) The boiling,melting point of organic compound is lass than inorganic compound.

3) Organic compound always contains carbon but inorganic compounds might not.

4) Organic compound

_____________________________

Ion and Radical Atoms:

In some sense they are a bit similar. The main difference is that a neutral radical has no charge imbalance between the protons and electrons, but the cation or anion does.

Ions are written with an explicit charge because of that charge imbalance, but radicals may or may not have an imbalance of charge. Just because a molecule is a radical doesn't mean it's neutral.

For example, if you shoot 2-pentanone with an electron beam for Electron "Impact" Mass Spectroscopy, where you essentially study molecules whose structures break into smaller pieces as a result of interacting with stray electrons to identify the molecules, you get a cationic radical (middle, or far right of the following diagram).

Answer: bromine

Explanation:

There are a total of 2+2+6+2+6+2+10+5=35 electrons, meaning there are 35 protons. The element with atomic number 35 is bromine

Answer:

c. a hypothesis  is the correct answer

Explanation:

The number of moles of H₂O is  0.36 mol.

The number of moles of LiClO₄ is  0.0521  mol.

Mole is an important standard unit used for the measurement of large quantities of atoms, molecules, or other particles. One mole is equal to 6.022×10²³ units.

The number of moles of a substance is calculated by:

Moles =[tex]\frac{mass}{molar \;mass}[/tex]

To find the number of moles of H₂O:

Mass of H₂O in the sample = 6.579 g

The molecular weight of H₂O = 18.02g

Moles = [tex]\frac{mass}{molar \;mass}[/tex]

Moles = [tex]\frac{6.579 g}{18.02g}[/tex]

Moles = 0.36

To find the number of moles of [tex]ZnSO_4[/tex]:

Mass of [tex]ZnSO_4[/tex] in the sample = 8.421 g

The molecular weight of [tex]ZnSO_4[/tex]= 161.47 g/mol

Moles =[tex]\frac{mass}{molar \;mass}[/tex]

Moles = [tex]\frac{8.421 g}{161.47 g/mol}[/tex]

Moles = 0.0521 moles

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From the calculations, the percentage of the mineral left is 6.25%.

The term half life refers to the time that it takes for only half of the number of radioactive isotopes to remain.

From;

N/No = (0.5)^t/t1/2

N = ?

No = ??

t = 2000

t1/2 = 500

N/No =(0.5)^(2000/500)

N/No = 0.0625

Thus the percent left = 0.0625 * 100 = 6.25%

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The AP Biology teacher is measuring out 638.0 g of dextrose (C6H12O6) for a lab the moles of dextrose is this equivalent to is 3.6888 moles.

A mole is described as 6.02214076 × 1023 of a few chemical unit, be it atoms, molecules, ions, or others. The mole is a handy unit to apply due to the tremendous variety of atoms, molecules, or others in any substance.

To calculate molar equivalents for every reagent, divide the moles of that reagent through the moles of the restricting reagent. The calculation is follows:

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52.66 grams of acetylene are in the tank.

PV=nRT is the formula for ideal gases, where P is the pressure and R is the constant and T is the temperature (P is 1.39 atm in this case)

Volume = 35.0 L

Gas constant = 0.08206 L.atm/K.mole

Temperature = 20.0 °C  = 293 °C

We also know that we can apply the formula ;

Number of mole(n) = [tex]\frac{MmPV}{RT}[/tex]

m = ( 26.04 × 1.39 × 35 )/ (0.08206 × 293.15)

m = 52.66 g

Thus, the mass is 52.66 grams.

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The granite block transferred 4,080 joules of energy, and the mass of the water is 35.8 grams.

Heat transfer in any system can be calculated as follow:

q = mCΔT

Given ;

Putting all the values in folowing equation,

q = mCΔT

we get

q = 126.1 × 0.795 × -40.7 = -4080 J

Now by using same formula, we can also calculate the mass of water in the following way:

m = q / CΔT

where

Putting all these values ;

m = -4080 /  4.186 × 27.2 = 35.8 g.

Hence, 4,080 joules of energy is transferred by granite block and 35.8 g is the mass of water.

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Answer:

sharks have cartilaginous skeletons

Explanation:

Sharks are an example

Answer:

It is in the same phase as the reactants.

Explanation:

i took the test

Answer:

Moles Lost = 0.0335 moles

Explanation:

This type of question requires the Ideal Gas Law equation. The equation looks like this:

PV = nRT

In this formula,

-----> P = pressure (kPa)

-----> V = volume (L)

-----> n = number of moles

-----> R = constant (8.314 L*kPa/mol*K)

-----> T = temperature (K)

(Step 1)

To find how many moles were lost, you first need to find how many moles you had to begin with. This can be done by plugging the starting values into the equation and solving for "n". But first, you need to convert Celsius to Kelvin (by adding 273.15).

P = 225 kPa                  R = 8.314 L*kPa/mol*K

V = 2.75 L                     T = 25°C + 273.15 = 298.15 K

n = ?

PV = nRT

(225 kPa)(2.75 L) = n(8.314 L*kPa/mol*K)(298.15 K)

618.75 = n(2478.8191)

0.250 = n

(Step 2)

Next, you need to find the number of moles in the container after it has been re-sealed. The volume is the same because the container did not change. The process should be the same as above.

P = 185 kPa                   R = 8.314 L*kPa/mol*K

V = 2.75 L                     T = 10°C + 273.15 = 283.15 K

n = ?

PV = nRT

(185 kPa)(2.75 L) = n(8.314 L*kPa/mol*K)(283.15 K)

508.75 = n(2354.1091)

0.216 = n

(Step 3)

Finally, you can find the number of moles lost by subtracting the final amount of moles from the original amount. When doing this calculation, I used the value of the moles saved in my calculator (with more decimal places) to get a more accurate number.

Moles Lost = Initial Moles - Final Moles

Moles Lost = 0.250 moles - 0.216 moles

Moles Lost = 0.0335 moles

The instability of the nucleus is due to an imbalance between the electrostatic and strong nuclear forces, which is option D.

A nucleus can become unstable if there is an imbalance between the electrostatic repulsion between protons and the strong nuclear force that holds the nucleus together. The electrostatic repulsion between protons tends to push them apart, while the strong nuclear force acts to hold the protons and neutrons together.

If the number of protons in the nucleus is too large, the electrostatic repulsion becomes stronger, making the nucleus unstable. Similarly, if the number of neutrons is too large or too small compared to the number of protons, it can also lead to an imbalance in the forces and instability of the nucleus.

Therefore, the correct option is option d.

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The approximate distance from the far edge of one lobe to the far edge of the other is 2,100,000 light-years.

This distance measures the outer space between the edges of the two lobes in a given time.

The approximate distance from the far edge of one lobe to the far edge of the other in a solar system is about 2,100,000 light-years.

Thus, the approximate distance from the far edge of one lobe to the far edge of the other is 2,100,000 light-years.

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Answer:

185 gms o NaBr

Explanation:

Na Br  mole weight = 22.989 +79.904 = 102.893  gm/mole

1.083 x 10^24  molecules / 6.022 x 10^23 molecules / mole = 1.798 moles

102.893  *  1.798 = 185 gms