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fiasKO [112]
3 years ago
9

Give the chemical symbol for one element with an electron configuration that ends with np2, where n is any principal quantum num

ber
Chemistry
1 answer:
Olenka [21]3 years ago
6 0
Remember any electronic configuration ending on np² means that it has a complete ns² orbital filled, So, the electronic configuration can be written as,

                                           ns², np²
Now,
       Let suppose n = 2, so the electronic configuration will be

                                          1s², 2s², 2p²

As n = 2 is the valence shell, so it belongs to 2nd Period.

As there are 4 electrons in valence shell, so, Group number is 4-A.

Looking at Period 2 and Group-IV A, the element found is,

                                              Carbon
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Archimedes tells us the lifting power of a balloon (how much mass it can lift) is equal to the difference between the mass of th
Finger [1]

Answer:

the Balogna could carry  19 passengers if filled with Hydrogen.

the Balogna could carry  17 passengers if filled with Helium.

Explanation:

Given that:

the radius of the cylinder r = 4.0 cm

the height h = 40 m

the volume of the cylinder will be:

V = \pi r^2 h

V = π (4.0 m)² (40)

V = 2010.62 m³.

where the density of the air = 1.23 kg/m³

the mass of the displaced air = Volume V ×density of the air

= 2010.62 m³ × 1.23 kg/m³

= 2473.0626 kg

To calculate how many passengers the Balogna could carry if it were filled with hydrogen, we have the following:

We are given the density of H₂ to be = 0.090 kg/m³

Therefore, the mass of Helium in the balloon = Volume V × density of the hydrogen

= 2010.62 m³ × 0.090 kg/m³

= 180.9558 kg

The total mass of the balloon = mass of H₂ + mass of empty balloon.

The total mass of the balloon = (180.9558+ 750) kg

= 930.9558 kg

Now, the Mass difference = mass of the air displaced -total mass of the balloon.

the Mass difference =  (2473.0626 - 930.9558 ) kg

the Mass difference =  1542.1068 kg

∴

number of persons = mass difference/ mass of passenger

the number of persons = 1542.1068 kg /80 (kg/person)

the number of persons = 19.27 persons

the number of passengers \simeq 19 passengers.

To calculate how many passengers the Balogna could carry if it were filled with helium, we have the following:

We are given the density of Helium to be =  0.18 kg/m³

Therefore, the mass of Helium in the balloon = Volume V × density of the hydrogen

= 2010.62 m³ × 0.18 kg/m³

= 361.9116 kg

The total mass of the balloon = mass of Helium + mass of empty balloon.

The total mass of the balloon = (361.9116 + 750) kg

= 1111.9116 kg

Now, the Mass difference = mass of the air displaced -total mass of the balloon.

the Mass difference =  (2473.0626 - 1111.9116 ) kg

the Mass difference =  1361.151 kg

∴

number of persons = mass difference/ mass of passenger

the number of persons =  1361.151 kg /80 (kg/person)

the number of persons = 17.01 persons

the number of passengers \simeq 17 passengers.

7 0
3 years ago
Having energy in the reactant lead to an exothermic reaction.<br>true<br>false​
Ostrovityanka [42]

Answer:

false

Explanation:

first of all;-energy lead to an indotermic reaction.

indotermic is a reaction that absorbs energy \

*it has positive enthalpy of reaction

*Heat content of product is greater than that of reactant

*Heat is added to reactant side

example;- CO^2+2H^2+891kj --------- CH4 +2O2

6 0
3 years ago
7. Which of the following statements about connecting paragraphs is correct?
Kitty [74]
The correct answer is D.
You can use a pointing word in paragraph two that refers to a word in paragraph one.
It is in connecting paragraph where we can use signal words or time signals to emphasize more on paragraphs. For example, second, meanwhile. 
7 0
3 years ago
For a solar eclipse to occur which of the following alignments is necessary? A. The moon is located along a straight line betwee
Aloiza [94]

For a solar eclipse t occur;

C. The moon is located from a line between the sun and earth

8 0
3 years ago
Según la Organización Mundial de la Salud, el nitrato de plata ( densidad = 4.35 g/cc ) es una sustancia con propiedades cáustic
OlgaM077 [116]

Answer:

737.52 mL de agua

Explanation:

En este caso solo debes usar la expresión de molaridad de una solución la cual es:

M = moles / V

Donde:

V: Volumen de solución.

Como queremos saber la cantidad de agua, queremos saber en otras palabras cual es la cantidad de solvente que se utilizó para preparar los 800 mL de disolución.

Una disolución se prepara con un soluto y solvente. El soluto lo tenemos, que es el nitrato de plata. Con la expresión de arriba, calculamos los moles de soluto, y luego su masa. Posteriormente, calculamos el volumen con la densidad, y finalmente podremos calcular el solvente de esta forma:

V ste = Vsol - Vsto

Primero calcularemos los moles de soluto:

moles = M * V

moles = 2 * 0.800 = 1.6 moles

Con estos moles, se calcula la masa usando el peso molecular reportado que es 169.87 g/mol:

m = moles * PM

m = 1.6 * 169.87 = 271.792 g

Ahora usando el valor de la densidad, calcularemos el volumen de soluto empleado:

d = m/V

V = m/d

V = 271.792 / 4.35

V = 62.48 mL

Finalmente, la cantidad de agua necesaria es:

V agua = 800 - 62.48

V agua = 737.52 mL

8 0
4 years ago
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