why do i have white spots on my teeth after brushing?

Answers

Answer 1
Fluorosis: Fluorosis can cause white spots due to exposure to excessive fluoride

Related Questions

How many molecules of NO2 are in 0.36 moles?

Answers

Answer:

1 mol contains 6.022*10^23 molecules 0.36 moles contain 0.36 * 6.022*10^23 = 2.2 *10^23 molecules

Explanation:

what should you do if your bunsen burner does not light after a few tries with the striker?

Answers

If the burner doesn't light after several strikes, turn the gas off at the source. Verify that you are generating sparks when striking the striker, and check that the barrel is all the way down and the needle valve is open by the specified amount. If these check out, the problem may be insufficient gas flow.

What halogen can react with sodium chloride solution to produce chlorine?

Answers

Answer:

As electro-negativity decreases from Florine to downwards in the group and only Florine is above Chlorine, so Florine should react with sodium chloride solution to produce chlorine.  

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Calculate the minimum volume of oxygen gas, at room temperature and pressure(r.t.p). required to completely burn 56g of methane gas. Give your answer to two significant figures. (1 mole of any gas occupies 24 dm³ at r.t.p,Ar:C=12,H=1)


BALANCED EQUATION FOR THE BURNING OF METHANE GAS.

CH₄+2O₂→CO₂+2H₂O

Answers

Answer:

170 dm³ (2 significant figures)

Explanation:

CH₄ + 2O₂ → CO₂ + 2H₂O

We need to find how much 'volume' of O₂ is required to burn 56 g of CH₄.

Let's take the ratios of the two gases only.

CH₄ : 2O₂ (in terms of moles the ratio is 1:2)

56g : x dm³

Mr of CH₄ : Volume of oxygen at rtp

Find the Mr of CH₄.

Mr of CH₄ = 12 + (1 × 4) = 16

We know that 1 mole of any gas occupies 24 dm³ at room temperature and pressure (rtp). We have to find the volume of oxygen, there are 2 moles of oxygen, so 2 moles of gas will occupy:

2 × 24 = 48 dm³

56g : x dm³

  16 : 48 dm³

16x = 56 × 48

16x = 2688

x = [tex]\frac{2688}{16}[/tex]

x = 168 dm³

∴ the minimum volume of oxygen gas, at room temperature and pressure required to completely burn 56g of methane gas is 170 dm³

Examples of errors in colorimetry experiments

Answers

Answer:

The lack of accuracy and underestimation of absorbance readings obtained from the colorimeter can be contributed to many experimental factors. One plausible error is from the imperfection of the absorber, in that it may not completely absorb the stray light passing by the perimeters of the photoresistor.

Explanation:

In practice there are other sources of error, such as environmental effects on photometer and sample, temperature, line voltage fluctuations, vibrations, contamination, or heating of the sample by the photometer. All these factors may impair the measured result, and ways and means are known to test and eliminate them.

PLZZZZ HELP MEEE I WILL GIVE BRAINLYEST I need more then ever so can you can pls help a bro out I need this done in before 5:00 it 2:00 now

Answers

Answer:

If it becomes buried deep into the earth and it is open to increased temperate and pressure. Then an Igneous rock could be Metamorphic. This process can take a lot of time but eventually the rock will change due to pressure andbhigher temperatures.

Fill in the blank:
A correctly written hypothesis uses an ____ ______ statement

Answers

Answer:

a theory of a experiment and the experiment acts like a judge determining if the hypothesis is right or wrong from the final test result

Explanation:

which is the correct formula for the compound dinitrogen monoxide?

Answers

Answer: Dinitrogen Monoxide ( also called nitrous oxide )

is an inorganic ( not made from living matter) compound with the chemical formula of N2O.

Explanation:

Read above

Does the amount of mentos affect the height of the pop explosion

Answers

Answer:

no

Explanation:

bcuz science

Answer:

The more mentos you put in a bottle of pop does not necessarily mean a larger explosion. The max amount of mentos with the largest explosion was 4 mentos, it went 350 cm high. With 5 or 6 mentos the explosion went only 330 and 310 cm high.

Hope this helped in some way?

5 Stoichiometry Chemistry questions !



1. Determine the mass in grams of lithium hydroxide produced when 0.38 g of lithium nitride reacts. g LiOH

Li3N(s) + 3 H2O(l) --> NH3(g) + 3 LiOH(aq)


2. How many moles of sodium chloride are produced when 2.9 grams of sodium iodide reacts? mol NaCl

2 NaI(s) + Cl2(g) --> 2 NaCl(s) + I2(g)


3. What volume in liters of chlorine gas at STP would be required to fully react with 125 g of NaI? L Cl2

2 NaI(s) + Cl2(g) --> 2 NaCl(s) + I2(g)


4. Determine the volume in liters of carbon dioxide produced at STP when 0.85 grams of butane (C4H10) reacts. L CO2

2 C4H10(l) + 13 O2(g) --> 8 CO2(g) + 10 H2O(g)


5. Calculate the mass in grams of water vapor produced by the combustion of 51.3 L of propane, C3H8, at STP. g H2O

C3H8(g) + 5 O2(g) --> 3 CO2(g) + 4 H2O(g)

Answers

Yea yea that’s what I mean it just depends what the people like

Maximum s-character is observed in
a) Triple bonded carbon atom b) Double bonded carbon atom
c) Single bonded carbon atom d) Carbon atom of benzene

Answers

[tex]\huge{\underline{\underline{\boxed{\sf{\purple{ǫᴜᴇsᴛɪᴏɴ}}}}}}[/tex]

Maximum s-character is observed ina) Triple bonded carbon atom b) Double bonded carbon atomc) Single bonded carbon atomd) Carbon atom of benzene

[tex]\huge{\underline{\underline{\boxed{\sf{\red{Answer}}}}}}[/tex]

Maximum s-character is observed ina) Triple bonded carbon atom

for the reaction 2nh3(g)↽−−⇀ 3h2(g)+n2(g), if 15.8 grams of ammonia produced 1.87g of hydrogen, what was the percent yield

Answers

Answer:

75%

Explanation:

So, the reaction will consume 1 mole of hydrogen gas and produce

1mole H2⋅2 moles NH33moles H2=0.667 moles NH3

at 100% yield. This represents the reaction's theoretical yield.

Now, you know that the reaction produced 0.50 moles of ammonia. This represents the reaction's actual yield.

In order to find the percent yield, you need to figure out how many moles of ammonia are actually produced for every 100 moles of ammonia that could theoretically be produced.

You know that 0.667 moles will produce 0.50 moles, so you can say that

100moles NH3.in theory⋅0.50 moles NH3.actual0.667moles NH3.in theory=75 moles NH3.actual

Therefore, you can say that the reaction has a percent yield equal to

% yield = 75%

How many atoms le aluminum are in this compound

Answers

I think it’s 2, hope this helps

What is the significance of cell division?
A. to make ATP
B. to prevent replication
C. to repair and replace other cells
D. to make glucose

Answers

The answer is c) to repair and replace other cells.

Cell division is the replication of cells by dividing itself into two, it does not prevent replication. Cell division does not make glucose either and cell division does not make ATP.

If the velocity of a wave is 12 m/s and its frequency is 600 hertz, what would be its wavelength?

Answers

Answer:

The wavelength is 0.02 m.

Step-by-step explanation:

Given :

[tex]\green\star[/tex] Velocity = 12 m/s[tex]\green\star[/tex] Frequency = 600 Hz

To Find :

[tex]\green\star[/tex] Wavelength

Using Formula :

Apply Wavelength formula :

[tex]\star{\small{\underline{\boxed{\sf{\purple{\lambda = \dfrac{v}{f}}}}}}}[/tex]

[tex]\pink\star[/tex] λ = Wavelength [tex]\pink\star[/tex] v = Velocity [tex]\pink\star[/tex] f = Frequency

Solution :

Finding the wavelength by substituting the values in the formula :

[tex]{\longrightarrow{\sf{\lambda = \dfrac{v}{f}}}}[/tex]

[tex]{\longrightarrow{\sf{\lambda = \dfrac{12}{600}}}}[/tex]

[tex]{\longrightarrow{\sf{\lambda = \dfrac{\cancel{12}}{\cancel{600}}}}}[/tex]

[tex]{\longrightarrow{\sf{\lambda = \dfrac{2}{100}}}}[/tex]

[tex]{\longrightarrow{\sf{\lambda = \cancel{\dfrac{2}{100}}}}}[/tex]

[tex]{\longrightarrow{\sf{\lambda = 0.02}}}[/tex]

[tex]\star{\underline{\boxed{\tt{\red{\lambda = 0.02 \: m}}}}}[/tex]

Hence, the wavelength is 0.02 m.

where does oxidation occur in an electrochemical cell

Answers

Anode


According to the mnemonic “Red Cat An Ox”, oxidation occurs at the anode and reduction occurs at the cathode. Since the reaction at the anode is the source of electrons for the current, the anode is the negative terminal for the galvanic cell.

explain a mixture of molecules

Answers

Answer:

A mixture of molecules is a group of molecules in which there are multiple different elements and atoms, that are in either fixed proportions or random. There are heterogeneous and homogenous mixtures.

Explanation:

Will give 10 points.
Why does an atom have a neutral charge?
A It has equal numbers of electrons and protons.
B. The number of neutrons equals the number of protons and
electrons in the atom.
C. It has equal numbers of electrons and neutrons.
D. It has equal numbers of neutrons and protons.

Answers

Answer:

option A it has equal numbers of electrons and protons

Explanation:

electrons are negatively charged and protons are positively charged, so if the numbers of each are equal, then the atom will be neutral.

Answer:

A. it has equal numbers of electrons and protons

Explanation:

The overall charge of every atoms is neutral because the number of electrons and protons is the same. Protons are positively charged while electrons are negatively charged and so they cancel out.

2. The two naturally occurring isotopes of hydrogen are hydrogen-1 ( 1.00783 amu; 99.9885 percent) and hydrogen-2 (2.01410 amu; 0.0115 percent). What is the average atomic mass of hydrogen?

A. 1.0079 amu
b. 1.0097 amu
c. 1.0309 amu
D. 1.5110 amu

Answers

The answer for your question is D

Answer:

1.0079 g/mol

Explanation:

99.989% / 100% = 0.99989 hydrigen-1 , 0.0115% / 100% = 0.000115 hydrogen-2

0.99989 x 1.0078 = 1.0077 ,  0.000115 x 2.0141= 0.000232

1.0077 + 0.00023

Answer: 1.0079

What is the chemical formula for nitrogen monoxide?

Answers

Answer: the formula is NO

how do particles in the most rigid state of matter move

Answers

Explanation: In solids, particles are very closely packed in an orderly arrangement in a lattice and only vibrate in fixed positions. The forces of attraction between them are very strong. This allows them to overcome the forces of attraction that hold the other phases closer together

What is the process that results in the formation of an ion

Answers

The answer is ionization

What is the Lewis structure for Iodide?

Answers

Answer:

In the Lewis structure for IF5 you'll need to put a total of 12 valence electrons on the Iodine atom in order to draw the Lewis structure. Remember that Iodine (I) can hold more than eight valence electrons. For the IF5 Lewis structure, calculate the total number of valence electrons for the IF5 molecule

Explanation:

I be knowing hope this helps

Which subatomic particles have a positive charge and are located in the nucleus?
a. neutrons
b. atoms
c. electrons
d. protons

Answers

Answer: protons

Explanation:

a) Neutrons are located in the nucleus but have a negative charge.

b) Atoms are not subatomic particles but are rather made of subatomic particles.

c) Electrons are subatomic particles with a negative charge that are located outside of the nucleus.

d) Protons are subatomic particles that are located in the nucleus and have a positive charge.

if a substance has a normal boiling point of 50 °c, what can you state about the vapor pressure of the same substance at 40 0 °c?

Answers

It will be less because pressure is directly proportional to temperature

Two samples of solids have similar reactivity with acids and similar densities. Their masses
and volumes, however, are not at all similar. Is it possible that these are the same
substance? (1 point)
O. No, it is not possible because they have different extensive properties.
O Yes, it is possible because they have similar intensive properties.
O Yes, it is possible because they have similar extensive properties.
O No, it is not possible because they have different intensive properties.

Answers

They may be the same substance even though they have different volumes and masses.

Intensive properties are the properties are characteristic  a substance. Intensive properties are those properties of a substance that can be used to describe the substance.

We can see that the substances have similar reactivity and similar density. This means that they may be the same substance even though they have different volumes and masses.

The correct option is; "Yes, it is possible because they have similar intensive properties."

Learn more: https://brainly.com/question/17323212

arrange the compounds from lowest boiling point to highest boiling point.

Answers

Answer:

ion- ion> H - bonding > dipole > dipole> london dispersion

4. Public water supplies are unsafe in some parts of the world because the water
and
may carry

Answers

Answer:

In many parts of the world, water taken directly from wells or public supplies is not safe to drink because it may carry waterborne parasites or other diseases. The water can be sterilized by boiling it, but fuel is needed to do so.

Explanation:

Answer:  Public water supplies are unsafe in some parts of the world because the water may carry bacteria.

Explanation:

can someone please explain how to find an emperical formula given mass not percentage?​

Answers

Answer:

1. Get the mass of each element by assuming a certain overall mass for the sample (100 g is a good mass to assume when working with percentages). ...

2. Convert the mass of each element to moles. ...

3. Find the ratio of the moles of each element. ..

4. Use the mole ratio to write the empirical fomula

Answer:

Multiply each result by the given mass.

Explanation:

Hi!

In order to find percent/mass composition you would

1. write the formula

2. calculate the molar mass for each equation

3. add all the masses to get the compound molar mass

4. divide each molar mass by the total mass

and then for mass composition, you would multiple eachy result by the given mass.

For example;

Calculate the number of grams of gold in 89.6 grams of gold(1) perchlorate.

Your formula would be AuClo4

Au : 196.96 x 1

Cl: 35.4 x 1

O: 16 x 4

Add the masses together to get 296.5 g/mol

Lets say we're looking for Oxygen. You would take what you got (16 x 4) and divide it by the total mass. 64/296.5

This would equal 0.215. Instead of multiplying this by 100 like you would for percent, for mass you would multiply by what is given. in this instance it is 89.6.

0.215 x 89.6 = 19

But the question is asking for gold,

197/296

= 0.664 x 89.6

= 59.5

Your answer would be 59.5 grams Au

Hope this helped! : D

Find the molar mass of iron (III) nitrate, Fe(NO3)3

Answers

Answer:

Hey there are you doing are you doing I will tell you the answer

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