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Answer:

0. 070g

Mass of 1 Si atom =28.08/6.022*1023

So mass 1.5 *1021*4.6629*10-23

Answer:

[tex]\boxed {\boxed {\sf 0.070 \ g \ Si}}[/tex]

Explanation:

We are given a value of atoms and asked to find the mass. We can complete this in 2 steps.

1. Convert Atoms to Moles

First, we have to convert atoms to moles. We use Avogadro's Number or 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance.

In this case, the particles are silicon atoms. We can set up a proportion.

[tex]\frac { 6.022 \times 10^{23} \ atom \ Si }{1 \ mol \ Si}[/tex]

Multiply by the value of atoms given.

[tex]1.5 \times 10^{21} \ atom \ Si *\frac { 6.022 \times 10^{23} \ atom \ Si }{1 \ mol \ Si}[/tex]

Flip the ratio. This allows the atoms of silicon units to cancel and leave the moles of silicon.

[tex]1.5 \times 10^{21} \ atom \ Si *\frac {1 \ mol \ Si } {6.022 \times 10^{23} \ atom \ Si}[/tex]

[tex]1.5 \times 10^{21}*\frac {1 \ mol \ Si } {6.022 \times 10^{23} }[/tex]

[tex]\frac {1.5 \times 10^{21} \ mol \ Si } {6.022 \times 10^{23} }[/tex]

[tex]0.002490866822 \ mol \ Si[/tex]

2. Convert Moles to Grams

Next, we convert the moles to grams. We use the molar mass, which is found on the Periodic Table. This value is the number of grams in 1 mole of a substance. Look for silicon (Si).

Use this value as a ratio.

[tex]\frac {28.085 \ g \ Si}{1 \ mol \ Si}[/tex]

Multiply by the number of moles we calculated.

[tex]0.002490866822 \ mol \ Si *\frac {28.085 \ g \ Si}{1 \ mol \ Si}[/tex]

The moles of silicon units cancel, so we are left with grams.

[tex]0.002490866822 *\frac {28.085 \ g \ Si}{1}[/tex]

[tex]0.002490866822 *{28.085 \ g \ Si}[/tex]

[tex]0.06995599469 \ g \ Si[/tex]

3. Round

Finally we must round our answer. The original value has 2 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place.

[tex]0.069\underline95599469 \ g Si[/tex]

The 9 tells us to round the other 9 to a 0, then the 6 to a 7.

[tex]0.070 \ g \ Si[/tex]

The mass of 1.5 × 10²¹ silicon atoms is 0.070 grams of silicon.

Answer:

B. Particles of matter have spaces between them.

Explanation:

The particle nature model of matter is an model used to explain the properties and nature of matter. The statements of the particle nature model of matter are as follows :

1. Matter is made of small particles of atoms or molecules.

2. The particles of matter have space between them. The spaces between the particles are least in solids as they are closely packed together but are greatest in gases whose particles are far apart from each other.

3. The particles of matter are in constant motion at all times. Solids particles are not free to move due to strong molecular forces between the particles, but are constantly vibrating in their mean positions. Liquid particles free to move due to lesser molecular forces while gas molecules which have negligible intermolecular forces have the greatest ability to move.

4. The particles of matter are attracted to each other by intermolecular forces. These forces are greatest in solids and least in gases.

The correct option is B.

Answer:

[tex]n_{Cl_2}=0.3molCl_2[/tex]

Explanation:

Hello there!

In this case, according to the given chemical reaction whereas the sodium chloride is in a 2:1 mole ratio with chlorine, the required moles of the later are computed as shown below:

[tex]n_{Cl_2}=0.6molNaCl*\frac{1molCl_2}{2molNaCl}[/tex]

So we cancel out the moles of NaCl to obtain:

[tex]n_{Cl_2}=0.3molCl_2[/tex]

Best regards!

Answer:

Matter is conserved during all chemical reactions because matter cannot be created or destroyed.

Explanation:

Answer:

Nuclear reactions involve a change in an atom's nucleus, usually producing a different element. Chemical reactions, on the other hand, involve only a rearrangement of electrons and do not involve changes in the nuclear.

Answer:there different from the rocky like planets gas giants don't have such a firm surface like rocky terrestrial planets

Explanation:

Answer:

A) w/w % of Fe - 2.44%

B) w/w % of Mg - 4.590%

C) w/w % of Ca - 96%

Explanation:

A) w/w % of Fe in limestone as Fe2O3 = (Mass of Fe2O3 /Mass of limestone) x 100

 0.0357/1.4639 X 100

= 2.438 =2.44

B) w/w % of Mg in limestone as Mg2P2O7 = (Mass of Mg2P2O7 /Mass of limestone) x 100

= 0.0672/1.4639 X 100

= 4.590

C) w/w % of Ca in limestone as CaSO4 = (Mass of CaSO4/Mass of limestone) x 100

= 1.4058/1.4639 X 100

= 96

Answer:Fe =1.71%    Ma=0.99%    Ca=28.24%

Explanation:

Answer:

1.55 × 10²⁴ atoms Xe

General Formulas and Concepts:

Atomic Structure

Stoichiometry

Explanation:

Step 1: Define

[Given] 57.5 L Xe at STP

[Solve] atoms Xe

Step 2: Identify Conversions

[STP] 22.4 L = 1 mol

Avogadro's Number

Step 3: Convert

Step 4: Check

Follow sig fig rules and round. We are given 3 sig figs.

1.54583 × 10²⁴ atoms Xe ≈ 1.55 × 10²⁴ atoms Xe

Answer:

pH = 8.18

Explanation:

The weak base, X, reacts with HCl as follows:

X + HCl → HX⁺ + Cl⁻

Where 1 mole of X with 1 mole of HCl produce 1 mole of HX⁺ (The conjugate acid of the weak base).

Now, using H-H equation for bases:

pOH = pKb + log [XH⁺] / [X]

Where pOH is the pOH of the buffer (pH = 14 -pOH)

pKb is -log Kb = 5.824

And [X] [HX⁺] are the molar concentrations of each specie

Now, at the neutralization of the half of HX⁺, the other half is as X, that means:

[X] = [HX⁺]

And:

pOH = pKb + log [HX⁺] / [X]

pOH = 5.824 + log 1

pOH = 5.824

pH = 14-pOH

Answer:

Learning the rock cycle and understanding the processes involved helps all of us. This is how soil forms, through the breakdown of rocks. We need soil to survive—imagine trying to grow vegetables without it. This is an immediate connection to the food chain

Answer:

C. or B.

Explanation:

The reason I chose c best, is when your cooking something with a pot with food in it max heat in about 5 minutes, the handle starts to get warmer every minute. This is conduction, where the heat transfers from the very bottom all the way to the very edge of something that is heated at a certain temperature.

Answer:

hard and brittle

hope this helps you ☺️☺️

good night take care sweet dream

Answer:

true

Explanation:

np have a good day brainliest?

Answer:

in my opinion I think the answer the be "A"

Answer:

1)2Na + Cl2 ----> 2NaCl

2)Ca + Br2 ---->CaBr2

3)K + H2O -----> KOH + H2

Answer:

B. aq if the reaction is inorganic (double or single displacement), neutralization, etc.

Explanation:

Hello there!

In this case, unfortunately we are not given the undergoing chemical reaction; however, in the most of the double displacement, neutralization, precipitation and in general, inorganic reactions, the hydrochloric acid must be B. aq as it must be dissolved in water as the reaction media. On the other hand, in some organic reactions, it can be either aqueous or gaseous, the latter, specially as a product. For that reason, you will need to make sure whether your reaction is organic or inorganic to correctly figure out the phase label.

Best regards!

Answer:

First balance the equation

C2H6 + 7/2O2 2CO2 +3H2O

for one mole of C2H6 there are 7/2 mole of O2 required. so for4.50 moles you require 4.50 x 7/2 = 15.75 moles of O2.

Explanation:

The Lewis base that we can see in the equation is [tex]H_{2} O[/tex]

We have to bear in mind that the Lewis base is the substance that is able to donate a pair of electrons. The substances that is able to accept the pair of electrons is what we call the Lewis acid.

The Lewis acid must possess a space for the addition of an electron pair while the Lewis base would have to be a specie that has a lone pair of electrons or has a negative charge. Thus the water molecule would serve as a Lewis base in this regard.

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Answer:

6 upper H subscript 2 upper O plus UPper C r (upper H subscript 2 upper O) subscript 6 superscript 3 plus.

✔ H2O or A.)

Cr3+

Cr(H2O)63+

Answer:

A water molecule displays polarity by having negative and positive ends. Due to this charge difference, a water molecule is called a dipole.

Explanation:

Answer:

a

Explanation:

Answer:

C₂H₅N₂

Explanation:

In the combustion analysis, all NO comes from the nitrogen of the sample, that means:

Moles NO = Moles N in the sample

In the same way:

Moles CO2 = Moles C in the sample

Moles H2O = 1/2 moles H in the sample

To solve this problem we must convert the mass of each gas to moles in order to find the moles of each atom. The empirical formula is the simplest whole number ratio of atoms presents in the molecule:

Moles NO = N -Molar mass: 30g/mol

0.4646g * (1mol / 30g) = 0.01549 moles N

Moles CO2 = C -Molar mass: 44.01g/mol-

0.6859g * (1mol / 44.01g) = 0.01559 moles C

Moles H2O = 1/2moles H -Molar mass: 18.02g/mol-

0.6973g * (1mol / 18.02g) = 0.03870 moles H

The ratio of atoms is -Dividing in the low number of moles = moles N-:

C = 0.01559 / 0.01549 = 1

N = 0.01549 / 0.01549 = 1

H = 0.03870 / 0.01549 = 2.5

Twice this ratio of atoms -Because empirical formula must be given only with whole numbers:

C = 2

N = 2

H = 5

The empirical formula is:

Answer:

genotype are the organism's hereditary information for example DNA

phenotype are the organism's physical characteristics for example your eyes or hair

or how your nose looks

Answer:

4.74

Explanation:

pH= -log[H+]

pH= -log(1.8 x 10^-5)= 4.74

Answer:

The balanced equation would be 2H2 + O2 -> 2H2O

Explanation:

The correct balanced equation is 2H₂ + O₂  →  2H₂O, and  the correct coefficient for O₂ is 1.

Count the atoms on each side first. Next, alter one of the compounds' coefficient. Third, count the atoms once more, and then repeat steps two and three until the equation is balanced.

In the given equation, hydrogens are already balanced. To balance oxygen, multiple water with 2. Thus, equation becomes:

H₂  + O₂  →  2 H₂O

Now, oxygen is balanced, just the hydrogens got unbalanced. To balance hydrogen, multiply the hydrogen by 2 on the left side.

2 H₂ + O₂  → 2H₂O

Now the chemical equation is balanced, in which the number of oxygen and hydrogen are equal on both sides of the arrow.

Therefore, the coefficient of O₂ is 1.

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Answer: a. Cathode

b. Galvanic cell

c. Anode

d. Electrolytic cell

e. half reaction

Explanation:

Galvanic cell or Electrochemical cell is defined as a device which is used for the conversion of the chemical energy produced in a spontaneous redox reaction into the electrical energy.

Electrolytic cell is a device where electrical energy is used to drive a non spontaneous chemical reaction.

In the electrochemical cell, the oxidation occurs at an anode which is a negative electrode and the reduction occurs at the cathode which is a positive electrode.  Thus the electrons are produced at anode and travel towards cathode.

The balanced two-half reactions will be:

Oxidation half reaction : [tex]M\rightarrow M^{n+}+ne^-[/tex]

Reduction half reaction : [tex]N^{n+}+ne^-\rightarrow N[/tex]

Thus the overall reaction will be: [tex]M+N^{n+}\rghtarrow M^{n+}+N[/tex]

Answer:

D and E

Explanation:

The other answers don't support steel, they support iron or are supporting both, and the question is why steel alloys are more often used

C supports both

B supports how iron's strength

A supports iron being easily shaped and bent

hope this helps

Answer:

[tex]T_2=484.8K[/tex]

Explanation:

Hello there!

In this case, according to the the variable temperature and pressure and constant volume, it turns out possible for us to calculate the new temperature via the Gay-Lussac's law as shown below:

[tex]\frac{T_2}{P_2} =\frac{T_1}{P_1}[/tex]

Thus, by solving for the final temperature, T2, we obtain:

[tex]T_2 =\frac{T_1P_2}{P_1}[/tex]

So we plug in the given data to obtain:

[tex]T_2 =\frac{303K*200atm}{125atm}\\\\T_2=484.8K[/tex]

Best regards!

Answer:

46.41%

Explanation:

Find the total r.m.m of AL(CLO3)3 put it equals to 100%.....The take 106.5,the total r.m.m of Cl and find the missing which is the percentage by cross multiplication