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prisoha [69]
3 years ago
7

A tiny pencil mark just visible to the naked eye contains about 3 × 1017 atoms of carbon. what is the mass of this pencil mark i

n grams?
Chemistry
1 answer:
Vera_Pavlovna [14]3 years ago
6 0
<span>The number of carbon atoms in the pencil mark is 3X1017 atoms of carbon The atomic weight of carbon is 12.01 amu, so 12.01 g of carbon contains 6.022X1023 atoms. Thus equation: 12.01 g carbon/ 6.022 X 1023 atoms (3X1017 atoms) (12.01 g carbon/ 6.022X1023 atoms) - the atoms cancel out (3X1017) (12.01g carbon/6.022X1023) divide and multiply = 6x10-6g carbon The mass of this pencil mark in grams is 6x10-6g carbon</span>
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Which is a property of barium (Ba)?
pogonyaev

Answer:

a it rarely reach with other elements

6 0
2 years ago
2.56 g of hydrogen reacts completely with 20.32 g of oxygen<br> to form X g of water. X = g
Brilliant_brown [7]

Answer:

Mass of water produced is 22.86 g.

Explanation:

Given data:

Mass of hydrogen = 2.56 g

Mass of oxygen = 20.32 g

Mass of water = ?

Solution:

Chemical equation:

2H₂ + O₂   →  2H₂O

Number of moles of oxygen:

Number of moles = mass/ molar mass

Number of moles = 20.32 g/ 32 g/mol

Number of moles = 0.635 mol

Number of moles of hydrogen:

Number of moles = mass/ molar mass

Number of moles = 2.56 g/ 2 g/mol

Number of moles = 1.28 mol

Now we will compare the moles of water with oxygen and hydrogen.

                    O₂            :            H₂O

                     1              :             2

                  0.635        ;            2×0.635 =  1.27

                   H₂             :              H₂O

                    2              :              2

                 1.28            :           1.28

The number of  moles of water produced by oxygen are less thus it will be limiting reactant.

Mass of water produced:

Mass = number of moles × molar mass

Mass = 1.27 × 18 g/mol

Mass = 22.86 g

 

4 0
3 years ago
Read 2 more answers
1.15 g of a metallic element needs 300 cm3 of oxygen for complete reaction, at 298 K and 1 atm
sashaice [31]
1) Calculate the number of moles of O2 (g) in 300 cm^3 of gas at 298 k and 1 atm


Ideal gas equation: pV = nRT => n = pV / RT


R = 0.0821 atm*liter/K*mol

V = 300 cm^3 = 0.300 liter

T = 298 K

p = 1 atm


=> n = 1 atm * 0.300 liter / [ (0.0821 atm*liter /K*mol) * 298K] = 0.01226 mol


2) The reaction of a metal with O2(g) to form an ionic compound (with O2- ions) is of the type


X (+) + O2 (g) ---> X2O          or   


2 X(2+) + O2(g) ----> X2O2 = 2XO     or


4X(3+) + 3O2(g) ---> 2X2O3


 
In the first case, 1 mol of metal react with 1 mol of O2(g); in the second case, 2 moles of metal react with 1 mol of O2(g); in the third, 4 moles of X react with 3 moles of O2(g)



So, lets probe those 3 cases.


3) Case 1: 1 mol of metal X / 1 mol O2(g) = x moles / 0.01226 mol

=> x = 0.01226 moles of metal X


Now you can calculate the atomic mass of the hypotethical metal:

1.15 grams / 0.01226 mol = 93.8 g / mol


That does not correspond to any of the metal with valence 1+


So, now probe the case 2.



4) Case 2:


2moles X metal / 1 mol O2(g) = x / 0.01226 mol


=> x = 2 * 0.01226 = 0.02452 mol


And the atomic mass of the metal is: 1.15 g / 0.02452 mol = 46.9 g/mol


That is similar to the atomic mass of titanium which is 47.9 g / mol and whose valece is 2+.


4) Case 3


4 mol meta X / 3 mol O2 = x / 0.01226 => x = 0.01226 * 4 / 3 = 0.01635 


atomic mass = 1.15 g / 0.01635 mol = 70.33 g/mol


That does not correspond to any metal.


Conclusion: the identity of the metallic element could be titanium.
5 0
3 years ago
La etiqueta de una bebida transparente con un ligero toque anaranjado indica que contiene aga con un 15 porciento de zumo de nar
Brilliant_brown [7]

<u>Respuesta:</u>

16 gramos de vitamina C y 8 gramos de colorantes.

Explanation:

Debemos multiplicar el porcentaje de cada componente por la cantidad total (100 %) de zumo.

800 g de zumo = 100%

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2/100 x 800 g = 16 g

- Tenemos un 1 porciento de colorantes en el zumo (1/100). Por lo tanto, la cantidad en gramos de colorantes es:

1/100 x 800 g = 8 g

6 0
2 years ago
Explain specifically how an electron gives off light in an atom.
exis [7]

Answer:

Then, at some point, these higher energy electrons give up their "extra" energy in the form of a photon of light, and fall back down to their original energy level.

Explanation:

When properly stimulated, electrons in these materials move from a lower level of energy up to a higher level of energy and occupy a different orbital.

3 0
2 years ago
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