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2 years ago

A toothpaste contains sodium fluoride (NaF) What percentage of Fluoride is present.(4cs)

Chemistry

1 answer:

MariettaO [177]2 years ago

7 0

Answer:

45.2%

Explanation:

To calculate the percent of an element in a compound we divide the molar mass of the element by the compound and multiply that by 100

First lets find the molar mass of Fluoride

Looking at the periodic table Fluoride has a molecular mass of 18.998 g

Now we need to find the molecular mass of NaF

Looking at a periodic table, Sodium (Na) has a molecular mass of 22.990g and Fluoride has a molecular mass of 18.998 so NaF has a molecular mass of 22.990(1) + 18.998(1) = 41.988g

Now we divide the mass of fluoride by the mass of sodium fluoride and multiply that by 100 to find the percentage of fluoride that is present in NaF

Mass of Fluoride = 18.998g

Mass of Sodium Fluoride = 41.988g

Percentage of fluoride present in NaF = (18.998g / 41.988g) * 100 = 45.2%

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The table lists properties of a few known elements, but the states of matter and melting points are missing. Look up the element

kolbaska11 [484]

The properties of the given elements are as follows:

Potassium, K;

State of matter: Solid
Melting point: 63.5 °C
Conductivity: Good
Solubility (H2O): reacts rapidly with water

Iodine, I;

State of matter: solid
Melting point: 113.5 °C
Conductivity: very poor
Solubility (H2O): negligible

Gold, Au;

State of matter: solid
Melting point: 1064 °C
Conductivity: excellent
Solubility (H2O): none

Germanium, Ge;

State of matter: solid
Melting point: 938.2 °C
Conductivity: fair
Solubility (H2O): none

Barium, Ba;

State of matter: solid
Melting point: 727 °C
Conductivity: good
Solubility (H2O): reacts strongly

Argon, Ar;

State of matter: gas
Melting point: -189.4 °C
Conductivity: none
Solubility (H2O): negligible

Chlorine Cl;

State of matter: gas
Melting point: -101.5 °C
Conductivity: poor
Solubility (H2O): slight

Rubidium, Rb;

State of matter: solid
Melting point: 39.48 °C
Conductivity: good
Solubility (H2O): reacts violently

Silver, Ag;

State of matter: solid
Melting point: 961.8 °C
Conductivity: excellent
Solubility (H2O): none

Calcium, Ca;

State of matter: solid
Melting point: 842 °C
Conductivity: good
Solubility (H2O): reacts

Silicon, Si;

State of matter: solid
Melting point: 1,410 °C
Conductivity: intermediate
Solubility (H2O): none

Xenon, Xe;

State of matter: gas
Melting point: -111.8 °C
Conductivity: very poor
Solubility (H2O): none

<h3>What are elements?</h3>

Elements are pure substances which are composed of similar atoms.

Elements are defined as substances which cannot be split into simpler substances by an ordinary chemical process.

Elements have different physical and chemical properties and can be classified into:

metals
semi-metals
non-metals

In conclusion, the physical and chemical properties of the elements vary from metals to non-metals.

Learn more about elements at: brainly.com/question/6258301

#SPJ1

7 0

1 year ago

a nuclide of 64/29 cu absorbs a positron. witch is the resulting atom? (A) 65/29Cu (B) 63/29 CU (C) 64/28Ni (D) 64/30 Zn

Nesterboy [21]

Answer : Option D) $Zn^{64}_{30}$

Explanation : When a positron is getting absorbed it means it will be $e^{+1}_{0}$ so, the $Cu^{64}_{29}$ will get converted;

So, the whole reaction will be;

$Cu^{64}_{29}$ + $e^{+1}_{0}$ ----> $Zn^{64}_{30}$ .

This will convert the whole element of Cu will get changed into Zn. As, it absorbs by the positron, the atomic number gets increased from 29 to 30.

4 0

3 years ago

Helpppppppppp!!!!!!!!!

professor190 [17]

Answer:

Explanation:

the solution is extremely acidic and will dissolve the zinc rod

3 0

3 years ago

Which of the following is not a form of radiation? Radio waves or sound waves or microwaves or gamma waves

Svetlanka [38]

Sound waves.
Radio waves and Microwaves are non-ionizing radiation. Gamma waves are ionizing radiation

3 0

2 years ago

How many grams of a stock solution that is 92.5 percent H2SO4 by mass would be needed to make 250 grams of a 35.0 percent by mas

IrinaVladis [17]

94.6 g. You must use 94.6 g of 92.5 % H_2SO_4 to make 250 g of 35.0 % H_2SO_4.

We can use a version of the dilution formula

m_1C_1 = m_2C_2

where

m represents the mass and

C represents the percent concentrations

We can rearrange the formula to get

m_2= m_1 × (C_1/C_2)

m_1 = 250 g; C_1 = 35.0 %

m_2 = ?; _____C_2 = 92.5 %

∴ m_2 = 250 g × (35.0 %/92.5 %) = 94.6 g

4 0

3 years ago