ellis measured the mass of five samples of quartz. his results were 39.75 g, 38.91 g, 37.66 g, 39.75 g, and 39.55 g. what was the mean mass of the samples? (p. 37

The result is a higher result than the correct value.

Gravimetric analysis describes a set of methods used in analytical chemistry for the quantitative determination of an analyte based on its mass. The principle of this type of analysis is that once an ion's mass has been determined as a unique compound, that known measurement can then be used to determine the same analyte's mass in a mixture, as long as the relative quantities of the other constituents are known.

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1. 92 g

2. 5.4 g

3. 0.217 moles

The mole is the number of particles(molecules, atoms, ions) contained in a substance  

1 mol = 6.02.10²³ particles

Can be formulated

N=n x No

N = number of particles

n = mol

No = Avogadro's = 6.02.10²³

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

[tex]\tt n=\dfrac{m}{MW}[/tex]

1. the mass of 4 moles of Na(MW= 23 g/mol)

[tex]\tt mass=mol\times MW\\\\mass=4\times 23\\\\mass=92~g[/tex]

2.  the mass of 0.3 moles of water(MW=18 g/mol)

[tex]\tt mass=mol\times MW\\\\mass=0.3\times 18\\\\mass=5.4~g[/tex]

3. the number of moles found in 10g of ethanol C2H5OH(MW=46 g/mol) :

[tex]\tt mol=\dfrac{10}{46}\\\\mol=0.217[/tex]

Answer:

choose a. 30 parts alcohol

Answer:

Balancing Chemical Equations

Balance the equations below:

1) __1__ N2 + __3__ H2      >       _2__ NH3

2) __2__ KClO3  >⮴ __2__ KCl + __3__ O2

3) __2__ NaCl + __1__ F2 ⮴ __2__ NaF + __1__ Cl2

4) __2__ H2 + __1__ O2 ⮴ __2__ H2O

5) __1__ Pb(OH)2 + __2__ HCl ⮴ __2__ H2O + __1__ PbCl2

6)__2__ AlBr3 + __3__ K2SO4 ⮴ __6__ KBr + __1__ Al2(SO4)3

7) __1__ CH4 + __2__ O2 ⮴ __1__ CO2 + __2__ H2O

8) _1___ C3H8 + _5___ O2 ⮴ __3__ CO2 + __4__ H2O

9) __2__ C8H18 + __25__ O2 ⮴ __16__ CO2 + __18__ H2O

10) __1__ FeCl3 + __3__ NaOH ⮴ __1__ Fe(OH)3 + __3__NaCl

11) __4__ P + __5__O2 ⮴ __2__P2O5

12) __2__ Na + __2__ H2O ⮴ __2__ NaOH + __1__H2

13) __2__ Ag2O ⮴ __4__ Ag + __1__O2

14) __1__ S8 + __12__O2 ⮴ __8__ SO3

15) _6___ CO2 + _6___ H2O ⮴ __1__ C6H12O6 + __6__O2

16) ___1_ K + __1__ MgBr ⮴ __1__ KBr + __1__ Mg

17) __2__ HCl + __1__ CaCO3 ⮴ __1__ CaCl2 + __1__H2O + __1__ CO2

18) __1__ HNO3 + __1__ NaHCO3 ⮴ __1__ NaNO3 + __1__ H2O + _1___ CO2

19) _2___ H2O + __1__ O2 ⮴ __2__ H2O2

20) __2__ NaBr + __1__ CaF2 ⮴ __2__ NaF + __1__ CaBr2

Explanation:

Answer:

The 10 kilogram ball

Explanation:

Answer: 0.3224, 7342, 54.32

Explanation:

0.1060 has 4 sig figs (1060 is 4 digits after the decimal point)

Answer:

1.5 × 10²⁴ atoms Mn

General Formulas and Concepts:

Chemistry - Atomic Structure

Explanation:

Step 1: Define

2.5 mol Mn

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

[tex]2.5 \ mol \ Mn(\frac{6.022 \cdot 10^{23} \ atoms \ Mn}{1 \ mol \ Mn} )[/tex] = 1.5055 × 10²⁴ atoms Mn

Step 4: Check

We are given 2 sig figs. Follow sig fig rules and round.

1.5055 × 10²⁴ atoms Mn ≈ 1.5 × 10²⁴ atoms Mn

The concentration of the KOH solution = 0.2064 M

Titration is a procedure for determining the concentration of a solution (analyte) by reacting with another solution whose known concentration (usually a standard solution) is called the titrant. Determination of the endpoint/equivalence point of the reaction can use indicators according to the appropriate pH range  

Acid-base titration formula  

Ma Va. na = Mb. Vb. nb  

Ma, Mb = acid base concentration  

Va, Vb = acid base volume  

na, nb = acid base valence  (number of ions H+/OH-)

a=H₂SO4(valence = 2, H₂SO4⇒2H⁺+SO₄²⁻, 2 ions H⁺)

b=KOH(valence = 1, KOH⇒K⁺+OH⁻, 1 ion OH⁻)

Ma = 0.15 M

Va = 17.2 cm³

Vb=25 cm³

The concentration of the KOH(Mb) :

[tex]\tt 0.15\times 17.2\times 2=Mb\times 25\times 1\\\\Mb=0.2064[/tex]

Answer:

Mass = 547.02 × 10⁻²³g

Explanation:

Given data:

Number of atoms of Al = 122 atom

Mass in gram = ?

Solution:

Avogadro number:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.  The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

122 atom/6.022 × 10²³ atoms ×  1 mol

20.26× 10⁻²³ mol

Mass in gram:

Mass = number of moles  × molar mass

Mass = 20.26× 10⁻²³ mol  × 27 g/mol

Mass = 547.02 × 10⁻²³g

Answer:

Average speed = 9.59 m/s

Explanation:

Given data:

Distance = 100 m

Time taken = 10.42 s

Average speed = ?

Solution:

Formula:

Average speed = distance covered / time taken

by putting values,

Average speed = 100 m / 10.42 s

Average speed = 9.59 m/s

(a) HCL(aq) + NaOH(aq)  ---------------> ___ + ____

The answer will be NaCl and H2O

(b) An equation to show the reaction between hydrogen ions and hydrogen ions and hydroxide ions is given below :

H+   +   OH−   ⇄ H2O

This reaction is known as neutralization reaction.

(c) Joey could tell us the reaction is over only when we obtained salt and water from the given chemical reaction (NaOH + HCl). This a basically a neutralization reaction ( the reaction  generally finished at equilibrium)

(d) pH is 7.

This is because at the ending point the moles of HCl = the moles of NaOH so all that is present is H2O, Cl–, and Na+. So, the pH is 7.

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Answer:

CH4 is a reactant

Explanation:

however 2o2 is also reactant but coefficient

ANSWER:

oil lol

EXPLANATION:

Answer:

Mineral oil, fragrance, aloe barbadensis leaf extract, tocopheryl acetate (vitamin E), water.

Explanation:

Answer:

Copper siliconquadoxide

Explanation:

Answer:

She okeyy

Explanation:

Example 740 are the think free ofıce pH of the blood 740 blood sample iş takipte kal ❣️

Answer:

Dicalcium phosphate. (I'm sure meant for the "o" to be an "a" for Calcium).

Explanation:

I hope this helps! :D Have a nice night!

The  original pressure of the gas : 2.507 atm

Boyle's law and Gay Lussac's law  

[tex]\tt \dfrac{P_1.V_1}{T_1}=\dfrac{P_2.V_2}{T_2}[/tex]

P1 = initial gas pressure (N/m² or Pa)  

V1 = initial gas volume (m³)  

P2 = final gas pressure  

V2 = final gas volume

T1 = initial gas temperature (K)  

T2 = final gas temperature  

V₁=28 L

T₁=45+273=318 K

P₂=2 atm

V₂=34 L

T₂=35+273=308 K

then initial pressure :

[tex]\tt P_1=\dfrac{P_2.V_2.T_1}{V_1.T_2}\\\\P_1=\dfrac{2\times 34\times 318}{28\times 308}\\\\P_1=2.507~atm[/tex]

The number of magnesium atoms present in forsterite are 10.272  x 10²³

First we have to calculate the moles of magnesium

moles of forsterite = mass of forsterite / molecular mass of forsterite

moles of forsterite = 120.0 g / 140.69 g/mol

moles of forsterite =  0.8529 mole

Now we have to calculate the number of magnesium atoms

The formula of  forsterite is mg2sio4

In the forsterite molecule, there 2 atoms of magnesium, 1 atoms of silicon and 4 atoms of oxygen.

As, 1 mole of forsterite contains 2 x 6.022 x 10²³ number of magnesium

So, 0.8529 mol of forsterite contains

= 0.8529 x 2 x 6.022 x 10²³

= 10.272  x 10²³ number of magnesium atoms

Therefore, the number of magnesium atoms present in forsterite are 10.272  x 10²³.

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Answer:

Smallest unit is called a formula unit

Forms between a metal and a nonmetal

Formed by the transfer of electrons

Good conductor when dissolved in water

Forms repeating patterns in a crystal lattice structure

Have high melting and boiling points

Explanation:

Conversion of 34.5  °C to K = C 307.65 K

Temperature is one of the principal quantities that shows the degree of heat or cold from an object / space  

Temperature is used as a guide to the level of heat energy from objects  

Temperature measures thermal energy  

The temperature conversion :

°F = (9/5) °C + 32

°R = (4/5) °C

°K = °C + 273 .15

34.5 °C into K

[tex]\tt 34.5+273.15=\boxed{\bold{307.65~K}}[/tex]

Answer:

Temperature is one of the principal quantities that shows the degree of heat or cold from an object / space  

Temperature is used as a guide to the level of heat energy from objects  

Temperature measures thermal energy  

The temperature conversion :

°F = (9/5) °C + 32

°R = (4/5) °C

°K = °C + 273 .15

Explanation:

false

Explanation:photosynthesis takes place inside an organelle called a chloroplast. For plants, chloroplast-containing cells exist in the mesophyll.

Answer:

Explanation:

The increase of the arable land has been affected partly by the reclamation of the marshes, but mostly by the transformation of large tracts of the puszta

An example of a reclamation is how landfill employees sift through garbage to find usable items. An example of a reclamation is trees growing on land that was heavily logged.

Answer:

Protons are the atomic number and for each element they never change.

Electrons are equal to the atomic number unless it is an Ion (Positive charge means it has less negative means it has more)

Mass number is Protons+Nuetrons

Explanation:

Answer:

P

Explanation:

radius decreases as you go from left to right