To determine the freezing point depression of a LiCl solution, Toni adds 0.317 g of LiCl to the sample test tube along with 20.5 mL of distilled water. Determine the concentration, in molality, of the resulting solution. MW of LiCl is 42.394 g/mol Density of H2O is 0.9982 g/mL

Solution

The mole is the number of particles contained in a substance

1 mol = 6.02.10²³

Moles can also be determined from the amount of substance mass and its molar mass

mol = mass : molar mass

mass = mol x molar mass

Molar mass = 58,6934 g/mol

Input the value :

mass = 0.0321 x 58,6934 g/mol

mass = 1.884 g

Answer:

Mass of NaF in 250 g tube of toothpaste = 100 mg of NaF

Explanation:

Mass of fluoride per gram of toothpaste = 1 mg

From the given data, the fluoride compound that is most often used in toothpaste is sodium fluoride, NaF, which is 45% fluoride by mass, mass of sodium fluoride per gram of toothpaste can be determined as follows:

1 mg of fluoride per gram of toothpaste = 45% total mass of NaF per gram of toothpaste

100% mass of NaF in toothpaste = 100/45 * 1 mg = 2.22 mg of NaF.

Therefore, mass of NaF per gram of toothpaste is 2.22 mg.

The mass of NaF in 250 g of toothpaste is then calculated below:

In 250 g of toothpaste, mass of NaF = 250 * 2.22 mg = 99.9 mg of NaF

Mass O2 = = 16.832 g

Given

43 grams of potassium chlorate

Required

Mass of O2

Solution

Reaction

2KClO3 ⇒3O2 + 2KCl

Mol KClO3 :

= mass : MW

= 43 g : 122,55 g/mol

= 0.3509

From the equation, mol O2 :

= 3/2 x moles KClO3

= 3/2 x 0.3509

= 0.526

Mass O2 :

= 0.526 x 32 g/mol

= 16.832 g

Answer:

32 days.

Explanation:

First we determine how much is made in a day.

16.50 x 4 = 66.

Next, we divide 2100 by 66 to reach our amount of days needed.

2100 / 66 = 31.818181... [81 is what repeats over and over.]

We round this up to the nearest whole number. You can't underpay, so you have to round.

The next whole number would be 32, so our answer is 32 days.

Answer:

Ice cap

Explanation:

See its polar so like north pole and north pole is ice cap.

Answer:

Ice cap

Explanation:

Answer:

See answer below

Explanation:

a.) Lithium Chloride, LiCl is soluble in water.

b.) Silver Chloride, AgCl is insoluble in water.

c.) Barium Carbonate, BaCO3 is insoluble in water.

d.)Potassium, K2 is soluble in water.

e.) Iron (III) Nitrate Fe(NO3)3 is soluble in water.

Answer:

Liquid oxygen evaporates at only a slightly higher temperature than liquid nitrogen because they have similarly low attraction between molecules. This would mean less liquid oxygen is coming out of tank 3 because some of it is evaporating as a gas instead.

The liquid oxygen machine is producing less liquid oxygen than normal because there's a low attraction between the molecules.

It should be noted that oxygen in its liquid state will take up less space. It can also be stored at a lower pressure than when it's in its gaseous state.

From the complete question, the liquid oxygen evaporates at a slightly higher temperature than the liquid nitrogen. The reason for this is due to the fact that they have similarly low attraction between molecules.

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The daughter isotope  : Radon-222 (Rn-222).

Given

Radium (Ra-226) undergoes an  alpha decay

Required

The daughter nuclide

Solution

Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,  

The decay reaction uses the principle: the sum of the atomic number and mass number before and after decay are the same

Radium (Ra-226) : ₈₈²²⁶Ra

Alpha particles : ₂⁴He

So Radon-226 emits alpha α particles ₂He⁴  , so the atomic number decreases by 2, mass number decreases by 4

The reaction :

₈₈²²⁶Ra ⇒ ₂⁴He + ₈₆²²²Rn

Answer:

the invention of the microscope has made seeing bacteria/cells, examining forensic evidence (such as fingerprints), studying atomic structure, tissue analysis, and the study of our ecosystem possible to the naked eye

Explanation:

hope this helps

Answer:

cell,tissue,organ,organ system,organism

Answer:The correct names for the structure are:

--> 1. 1-bromo-3-chlorobenzene.

--> 3. meta-bromochlorobenzene.

--> 6. m-bromochlorobenzene.

Explanation:

Benzene is the simplest member of the aromatic hydrocarbons. It has a ring structure consisting of six carbon and six hydrogen atoms. This equally means that a benzene can have up to six substituents. One of the chemical properties is that benzene and other members of its series undergo substitution reaction whereby one or more of its six hydrogen atoms is replaced by monoatomic reagents.

Disubstituted benzene consists of two substituents which are described based on either numerical locants or specific words for the three possible forms.

The numerical locant method are used the same naming substitutes of other hydrocarbons. From the question, the numerical locant method was derived through using the following steps:

--> the functional group is benzene

--> there are two substituents which includes bromine( written as bromo) and chlorine ( written as chloro)

--> while placing the number, it's done alphabetically ('1-bromo' comes before '3-chloro') in a clockwise manner. This is to give chorine the lowest locant number.

The second naming method for a disubstituted benzene is the the ortho-, meta-, para- (or their singel letter equivalent) nomenclature method. This is only used for benzene structures.

--> ortho or O : this is used when the substituents are close to each other in the benzene ring.

--> meta or (m) : This is used when the substituents are separated by one carbon in the benzene ring.

--> para or (p): This is used when the substituents are across each other in the benzene ring

From the question, the bromine substituent is separated from the chlorine by one carbon atom, therefore it's meta-bromochlorobenzene or m-bromochlorobenzene.

Answer:

Explanation:

4 Li(s) + 1 O2(g) -> 2 Li2O(s)

To calculate the atoms of an element in a given molecule, we need to multiply stoichiometry by the number that is written on the foot of that element. Therefore, the balanced equation is 4 Li(s) + 1 O[tex]_2[/tex](g) [tex]\rightarrow[/tex] 2 Li[tex]_2[/tex]O(s).

Balanced equation is the one in which the total number of atoms of a species on reactant side is equal to the total number of atoms on product side. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, displacement reaction.

The other characteristic of balanced reaction is that physical state should be written with each compound or molecule on reactant and product side. Physical state should be written in brackets. s means solid, l means liquid, g means gas. The balanced equation for the given reaction is 4 Li(s) + 1 O[tex]_2[/tex](g) [tex]\rightarrow[/tex] 2 Li[tex]_2[/tex]O(s)

Therefore, the balanced equation is 4 Li(s) + 1 O[tex]_2[/tex](g) [tex]\rightarrow[/tex] 2 Li[tex]_2[/tex]O(s).

Learn more about the balanced equation, here:

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Answer:

products

Explanation:

yeah the answer is product

Answer:

Option C

Explanation:

The answer is option C or "The amount of time it takes to rotate around it's axis is the same amount of time it takes to revolve around Earth."Remember that the Earth and the Moons amount of time to make a full rotation is almost in sync and they're two sides of the moon, one side we do not see and that's because that side is currently faced away from the Earth which is called the dark side of the moon. Each side has two weeks oh night, and two weeks of day because of how long it takes the moon to revolve, so while we have a side towards the Earth which is illuminated by the sun we have another pointing away in the dark.

Hope this helps.

Given

Atomic symbol

Required

Atomic composition

Solution

Atomic number = number of protons = number of electrons

Mass Number (A) is the sum of protons and neutrons

Number of protons and Number of Neutrons  in nucleus

Number of electrons in the shell

From the picture:

protons = 3

neutrons = 4

electrons = 3

atomic number = protons = electrons = 3

mass number = protons + neutrons = 3+4 = 7

Answer:

55.6 °C

Explanation:

From the question given above, the following data were obtained:

Mass (M) of diamond = 32.0 g

Initial temperature (T₁) = 33.5°C

Heat (Q) required = 360 J

Specific heat capacity (C) of diamond = 0.509 J/gºC

Final temperature (T₂) =?

Next, we shall determine the change in temperature. This can be obtained as follow:

The final temperature can be obtained as follow:

Mass (M) of diamond = 32.0 g

Heat (Q) required = 360 J

Specific heat capacity (C) of diamond = 0.509 J/gºC

Change in temperature (ΔT ) =?

Q = MCΔT

360 = 32 × 0.509 × ΔT

360 = 16.288 × ΔT

Divide both side by 16.288

ΔT = 360 / 16.288

ΔT = 22.1 °C

Finally, we shall determine the final temperature. This can be obtained as follow:

Initial temperature (T₁) = 33.5°C

Change in temperature (ΔT ) = 22.1 °C

Final temperature (T₂) =?

ΔT = T₂ – T₁

22.1 = T₂ – 33.5

Collect like terms

22.1 + 33.5 = T₂

T₂ = 55.6 °C

Therefore, the final temperature is 55.6 °C.

Answer:

Nickel

Explanation:

Given data:

Density of iron = 7.9 g/cm³

Density of lead = 11.3 g/cm³

Density of nickel = 8.9 g/cm³

Mass of sample = 134 g

Volume of sample = 15 cm³

Which metal it is = ?

Solution:

First of all we will calculate the density of sample and then match it with the density of given metals.

Formula:

d = m/v

by putting values,

d = 134 g/ 15 cm³

d = 8.9 g/cm³

The weighted sample is nickel metal.

the answer Is A hope it helps

Answer:

NaBH₄

Explanation:

First, we need to write the chemical formula of all the compounds:

Benzil: C₁₄H₁₀O₂

Sodium Borhydride: C₁₄H₁₀O₂

Hydrobenzoin: C₁₄H₁₄O₂

Now, let's write the reaction that is taking place and write all the products:

C₁₄H₁₀O₂ + 2NaBH₄ + 2H₂O -----------> C₁₄H₁₄O₂ + 2BH₃ + 2NaOH

We can see that the reaction is already balanced, so we don't need to do anything else.

The question of this exercise is to determine the limiting reagent of the reaction, in other words, the reagent that controls the reaction and produces the 2.22 g of the hydrobenzoin. And to know this we need to see the mole ratio in both reactants, and compare them to the given moles (That can be obtained with the given masses and MW)

According to the above reaction, we have a mole ratio of 1:2, so, let's calculate the moles of benzil and the borohydride, and see which of them is the limiting reactant:

moles C₁₄H₁₀O₂ = 2.56 / 210.23 = 0.0122 moles

moles NaBH₄ = 0.38 / 37.83 = 0.01 moles

moles  C₁₄H₁₄O₂ = 2.22 / 214.26 = 0.0103 moles

We have the moles of every species, now, let's see the mole ratio

If 1 mole of C₁₄H₁₀O₂ -----------> 2 moles of NaBH₄

Then 0.0122 moles C₁₄H₁₀O₂ ----------> X moles of NaBH₄

Solving for X:

X = 0.0122 * 2 / 1 = 0.0244 moles of NaBH₄ are required.

However, we only have 0.01 moles of NaBH₄, and we need so much more of this to completely react with the moles of the benzil. Therefore we can safely assume that the limiting reagent is the NaBH₄

Another data that we can use for this, is the fact the produced moles were 0.0103, and this value is nearest to the moles of NaBH₄ rather than the moles of the benzil.

Hope this helps

Answer:

monosaccharides and glycosidic, I think

Explanation:

Answer:

pasagottt po plss

Explanation:

edi wow

Answer:

Chlorophyll is one. I can't quite remember other

Answer:

50g

Explanation:

At the end of the burning process, the mass of the jar and smoke should be 50g after the candle burning is done.

In most systems, the law of conservation of matter finds expression. According to this law "matter is neither created nor destroyed but atoms are rearranged".

In this kind of system, no matter is allowed to escaped and the starting mass of the reactants compared to that of the product will be the same.

Answer:

Some substances can change from the solid state to the gas state without ever becoming a liquid. During this process, known as sublimation, the sur- face particles of the solid gain enough energy to become a gas.When dry ice becomes a gas, it absorbs thermal energy from water vapor in the air.

Explanation:

Answer:

temperature of the reaction vessel

Explanation:

temperature of the reaction vessel

The value of the rate constant for a gas phase chemical reaction can be changed by increasing the: A. temperature of the reaction vessel.

In Chemistry, rate constant is typically used with rate law to tell the reaction rate or rate of a chemical reaction that is affected by activation energy.

Mathematically, the rate law is given by this formula:

[tex]R = k[A]^x[B]^y[/tex]

Where:

Generally, the value of the rate constant for a gas phase chemical reaction can be changed by increasing the temperature of the vessel (container) that is used in conducting the chemical reaction.

Read more on rate constant here: brainly.com/question/24749252

Answer:

one mole of oxygen will produce [tex]0.4[/tex] moles of water

Explanation:

The balanced chemical reaction is as follows -

2 C2H2 + 5 O2 --> 4 CO2 + 2 H2O

As we can see in this reaction

5 mole of oxygen (on the reactant side) will produce 2 mole of water (on the product side)

Hence, one mole of oxygen will produce [tex]\frac{2}{5} =0.4[/tex] moles of water

Answer:

See explanation below

Explanation:

In this case, we can use the Boyle's law. Assuming that the temperature of both trial remains constant, then:

P₁V₁ = P₂V₂    (1)

You should note that this expression is usable when you are dealing with gases. However, we can treat this unknown liquid as a gas, because all the air on the flask is removed, and we can assume that the liquid can behave like an ideal gas.

So using the above expression, we can solve for P₂:

P₂ = P₁V₁ / V₂    (2)

In this case, we already have the values of presures and volume, so replacing in this expression:

P₂ = 34.5 * 5 / 214

This should be the pressure of the liquid.

Hope this helps