Please help!!!!!!!!!!!!!!!!!!!

Answer:

the amount of valence electron, cna be found in the periodic table, which is called the atomic number which is top of the symbol

hope this helps!!! best fo luck to you

Explanation:

I did it step by step so It would be easier to understand:)

Answer:

Percentage of copper in sample = 60%

Explanation:

Given:

Mass of copper = 150 gram

Mass of brass = 250 gram

Find:

Percentage of copper in sample

Computation:

Percentage of copper in sample = [Mass of copper / Mass of brass]100

Percentage of copper in sample = [150/250]100

Percentage of copper in sample = [0.6]100

Percentage of copper in sample = 60%

Answer:the second largest one

Explanation:

both weels are pushing at it

Answer:

A. Li= 5.6 g O2= 6.4 g

Explanation:

Lithium oxide, Li2O, is an oxide that contains 2 moles of Li and 1 mole of O per mole of oxide. To solve this question we must find the mass of each atom in the molecule as follows:

2Li = 2*6.941g/mol = 13.882g/mol

O = 1*16g/mol = 16g/mol

Molar mass Li2O:

16+13.882 = 29.882g/mol

The mass of lithium is:

12g * (13.882g/mol / 29.882g/mol) = 5.6g Li

And the mass of oxygen:

12g * (16g/mol / 29.882g/mol) = 6.4g O

Right answer is:

Answer: cuhh

Explanation:

Answer:

342.15 g/mol

..........

Answer:

K2O Potassium oxide

Explanation:

Answer:

There are 0.5 mole in 20g of argon.

Explanation:

40 g of argon = 1mole

Then 20g of argon is,

→ 1/40 × 20

→ 0.5 mole

Answer:

[tex]n = \frac{mass}{molar \: mass} \\ n = \frac{20g}{39.948 \frac{g}{mol} } \\ n = 0.5 \: mol \: of \: argon[/tex]

Explanation:

hope this makes sense

:)

Answer:

may be the answer is Heat and pressure - melting - cooling

Answer:

hi!

Explanation:

Well, some things I would do is to know the Periodic Table font and back. Know they elements and their class and atomic number and weight. Know how many atoms make up each element and how many protons, neutrons, and elements are in each atom.

Answer:

88,88 % de O y 11,11 % de H

Explanation:

La composición porcentual se define como la masa que hay de cada mol de átomo en 100g. Las moles de agua en 100g son:

Masa molar agua:

2H = 2*1g/mol = 2g/mol

1O = 1*16g/mol = 16g/mol

Masa molar = 2 + 16 = 18g/mol

100g H2O * (1mol / 18g) = 5.556 moles H2O.

Moles de hidrógeno:

5.556 moles H2O * (2mol H / 1mol H2O) = 11.11 moles H

Moles Oxígeno = Moles H2O = 5.556 moles

La masa de hidrógeno es:

11.11mol * (1g/mol) 11.11g H

La masa de oxígeno es:

5.556 mol * (16g / 1mol) = 88.89g O

Así, el porcentaje de O es 88.89% y el de H es 11.11%. La opción correcta es:

Answer:

their mobile electrons

The above given statement is true.

A homogeneous mixture comprised of two or more components is referred to as a solution. Because they are consistently scattered at the molecular or ionic level, the components in a solution are evenly mixed and have a constant composition.

Until the reaction between the two solutions is complete, a solution of known concentration is gradually added to a solution of unknown concentration in a titration. The endpoint, or point at which the reaction is finished, is often identified by a color change that takes place after an indicator is added to the solution being titrated.

The reaction has achieved its endpoint when the solution in the flask changes color, and the new color persists even after the solution is gently shaken. At this time, the titration should be halted. By doing this, it is possible to precisely determine the concentration of the unknown solution and the volume of titrant added to the solution.

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Answer:

Explanation:

The answer is C Enthaply and entropy because temperature plays a big role in reactions

Answer:

c

Explanation:

a p e x :)

Answer:

1. Hidracidas a. MX

2 Acidas c. MHXO

3. Oxacidas  b. MXO

4. Basicas d. M(OH)X

Explanation:

¡Hola!

En este caso, de acuerdo con el concepto de sal, la cual está generalmente dada por la presencia de al menos un metal y un no metal, es posible encontrar cuatro tipos de estas; hidrácidas, oxácidas, básicas y ácidas, en las que las primeras dos son neutras pero la segunda tiene presencia de oxígeno, la tercera tiene iones hidróxido adicionales y la cuarta iones hidrógeno de más.

Debido a la anterior, es posible relacionar cada pareja de la siguiente manera:

1. Hidracidas a. MX

2 Acidas c. MHXO

3. Oxacidas  b. MXO

4. Basicas d. M(OH)XO

En las que M se refiere a un metal, X a un no metal, H a hidrógeno y O a oxígeno.

¡Saludos!

Answer:

Im not 100% sure this is correct but i think the answer would be  

Both authors show the main characters being labeled in a negative manner based on their appearances.

Explanation:

because

both the ugly ducking and the princess are not in the best conditions so i think that would be why that is the answer choice

Answer: i think it's  Both authors show the main characters being labeled in a negative manner based on their appearances.

Explanation: they both are being labeled in a negative manner so that's your answer your welcome

Answer:

33 moles

Explanation:

The given chemical reaction is 2C₄H₁₀(g) + 13 O₂(g) → 10H₂O(g) + 8CO₂(g)

The number of moles of each reactant are as follows;

Butane, C₄H₁₀ = 2 moles of (g) + 13 (g) → 10H₂O(g) + 8CO₂(g)

Oxygen gas, O₂ = 13 moles

Water, H₂O = 10 moles

Carbon dioxide, CO₂ = 8 moles

The total number of moles, n = (2 + 13 + 10 + 8) = 33

∴ The total number of moles involved in the reaction, n = 33 moles.

Answer:

2 moles of ammonia gas (NH₃) reacts with 5/2 moles of oxygen gas (O₂) to produce 2 moles of nitrogen monoxide gas (NO) and 3 moles of liquid water (H₂O)

Explanation:

The chemical equation is:

NH₃(g) + O₂(g)⇒ NO(g) + H₂O(I)

First, we have to distinguish which are reactants and which are products.

Reactants ⇒ left side: NH₃ (ammonia gas) and O₂ (oxygen gas)

Products ⇒ right side: NO (nitrogen monoxide) and H₂O (water)

Thus, ammonia gas reacts with oxygen gas to produce nitrogen monoxide gas and liquid water.

The reaction is not balanced, because it does not has the same number of atoms of each chemical element in both sides. To balance, we have to write a coefficient of 3 for H₂O, then a coefficient of 2 for NH₃ (to balance H atoms), then a coefficient of 2 for NO, and finally a coefficient of 5/2 for O₂ (to obtain 5 atoms of O in both sides):

2 NH₃(g) + 5/2 O₂(g)⇒ 2 NO(g) + 3 H₂O(I)

According to the balanced equation, 2 moles of ammonia gas (NH₃) reacts with 5/2 moles of oxygen gas (O₂) to produce 2 moles of nitrogen monoxide gas (NO) and 3 moles of liquid water (H₂O).

Answer:

7800 cells

Explanation:

The number of Escherichia coli cells N after n generations is given by

N = 2ⁿ × N₀ where N₀ = initial population

Now making N₀ subject of the formula, we have

N₀ = N/2ⁿ

Since n = 8 and N = 1,996,800 cells, substituting the values of the variables into the equation, we have

N₀ = N/2ⁿ

N₀ = 1,996,800 cells/2⁸

N₀ = 1,996,800 cells/256

N₀ = 7800 cells

So, the initial population of Escherichia coli cells is 7800 cells.

Answer:

It should have about 70-80 pounds of air pressure.

Answer:

5 lbs is what I read on the internetluv </3

Answer:

d

Explanation:

the answer is d is that correct

Answer:

34.78% Fe

39.66% Cu

5.48% S

20.07% O

Explanation:

Para resolver esta pregunta debemos hallar la masa de cada átomo en cada mineral. Así, podremos hallar el porcentaje de cada átomo:

Pirita (Fe: 55.845g/mol; S: 32.065g/mol; FeS2: 119.975g/mol)

Masa Fe:

20kg FeS2 * (1*55.845g/mol / 119.975g/mol) = 9.31kg Fe

Masa S:

20kg FeS2 * (2*32.065g/mol / 119.975g/mol) = 10.69kg S

Hemetita (Fe: 55.845g/mol; O: 16g/mol; Fe2O3: 159.688g/mol)

Masa Fe:

70kg Fe2O3 * (2*55.845g/mol / 159.688g/mol) = 48.96kg Fe

Masa O:

70kg Fe2O3 * (3*16g/mol / 159.688g/mol) = 21.04kg O

Calcopirita (Fe: 55.845g/mol; Cu: 63.546g/mol; CuFe2: 175.236 g/mol)

Masa Fe:

15kg CuFe2 * (2*55.845g/mol / 175.236 g/mol) = 9.56kg Fe

Masa Cu:

15kg CuFe2 * (1*63.546g/mol / 175.236 g/mol) = 5.44kg Cu

Tenorita (O: 16g/mol; Cu: 63.546g/mol; CuO: 79.545 g/mol)

Masa O:

90kg CuO * (1*16g/mol / 79.545 g/mol) = 18.10kg O

Masa Cu:

90kg CuO * (1*63.546g/mol / 79.545 g/mol) = 71.90kg Cu

Masa Total: 20kg + 70kg + 15kg + 90kg = 195kg

Porcentaje Hierro:

9.31kg Fe + 48.96kg Fe + 9.56kg Fe / 195kg * 100 =

34.78% Fe

Porcentaje Cobre:

5.44kg Cu + 71.90kg Cu / 195kg * 100 =

39.66% Cu

Porcentaje Azufre:

10.69kg S / 195kg * 100 =

5.48% S

Porcentaje Oxígeno:

21.04kg O + 18.10kg O/ 195kg * 100 =

20.07% O

Answer:

C

Explanation:

The phosphate group PO4 is bonded covalently (bond between two non metals). While the sodium being bonded to the phosphorus atom is an ionic bond (bond between a metal and a non metal)

The chemical bonding in sodium phosphate, Na3PO4 is classified as both covalent and ionic. Therefore, option C is correct.

An enduring attraction between atoms or ions known as a chemical bond is what allows molecules and crystals to form. The bond may be created by the sharing of electrons in covalent bonds or by the electrostatic attraction of two oppositely charged ions, as in ionic bonds.

Chemical bonds are formed when the atoms in a compound's molecule are brought together and kept together by a powerful combining force. Ionic and covalent bonds are the two different types of chemical bonds.

Molecules are held together by chemical bonds, which also make transient connections necessary for life. chemical bonds, including as ionic, covalent, and hydrogen bonds, as well as London dispersion forces.

Thus, option C is correct.

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Answer:a)No of moles of Aluminium=0.4703

b)number of aluminum atoms=2.832 x 10^23 atoms

Explanation:

a)Given that The Amount/ Mass of Aluminum is 12.69g

We know that

No of moles =Mass/ Molar mass

Molar mass of Aluminium, Al is 26.982 g/mol

No of moles =12.69g/26.982 g/mol

No of moles =0.4703

Also

b) 1  mole of aluminium must contain  6.022  x 10^23  atoms of aluminium  

which is  known as Avogadro's constant.

Therefore, 0.4703 moles will contain 0.4703 x  6.022  x 10^23  atoms =2.832 x 10^23 atoms

Answer: There are [tex]2.032 \times 10^{25}[/tex] molecules [tex]S_{2}[/tex] gas are in 756.2 L.

Explanation:

It is known that 1 mole of any gas equals 22.4 L at STP. Hence, number of  moles present in 756.2 L are calculated as follows.

[tex]Mole = \frac{Volume}{22.4 L}\\= \frac{756.2 L}{22.4 L}\\= 33.76 mol[/tex]

According to mole concept, 1 mole of every substance contains [tex]6.022 \times 10^{23}[/tex] molecules.

Therefore, molecules of S present in 33.76 moles are calculated as follows.

[tex]1 mol = 6.022 \times 10^{23}\\33.76 mol = 33.76 \times 6.022 \times 10^{23}\\= 2.032 \times 10^{25}[/tex]

Thus, we can conclude that there are [tex]2.032 \times 10^{25}[/tex] molecules [tex]S_{2}[/tex] gas are in 756.2 L.

Answer:

red and blue

Explanation:

Explanation:

this is ur answer i hope.........