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3 years ago

How many dots are shown in the electron dot diagram for calcium, element number 20?

Chemistry

1 answer:

kykrilka [37]3 years ago

4 0

2 dots are shown for drawing it. because it has two valence electrons

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A compound that contains 63.15% carbon,5.30% hydrogen and the remaining percent oxygen

tamaranim1 [39]

Oxygen percentage is 31.55%

4 0

3 years ago

Charles’ Law can be expressed mathematically as V=kT. If the constant k for 6.0 L of gas is 0.020 L/K (liters per kelvin), what

kozerog [31]

Answer: 300 K

Explanation:

Charles' Law: This law states that volume is directly proportional to the temperature of the gas at constant pressure and number of moles.

$V\propto T$ (At constant pressure and number of moles)

$V=kT$

Given : V= 6.0 L

k= 0.020 L/K

T=?

$6.0=0.020LK^{-1}\times T$

$T=300 K$

Thus temperature of the gas is 300 K.

3 0

3 years ago

Which of the following equations has correct formulas and also is a balanced equation?

aliya0001 [1]

Answer : The correct option is, (B)

Explanation :

Balance equation : Balanced equation are those equation in which the number of atoms of each element and the total charge must be same on products side and reactants side.

In the given options, only option (B) equation has correct formula and also a balanced equation.

$2Be+O_2\rightarrow 2BeO$

while the other options has incorrect formulas and also an unbalanced equations.

The correct equation for option A is, $CaCO_3\rightarrow CaO+CO_2$

The correct equation for option C is, $2Mg+O_2\rightarrow 2MgO$

The correct equation for option D is, $KCl+HNO_3\rightarrow HCl+KNO_3$

Hence, the correct answer is, (B) $2Be+O_2\rightarrow 2BeO$

5 0

3 years ago

Calculate the molality of a 5.73 M ethanol (C2H5OH) solution whose density is 0.9327 g/mL.

Natalka [10]

Answer:

Molality = 8.57 m

Explanation:

Given data:

Molarity of solution = 5.73 M

density = 0.9327 g/mL

Molality of solution = ?

Solution:

Molality = moles of solute / kg of solvent.

Kg of solvent:

Mass of 1 L solution = density× volume

Mass of 1 L solution = 0.9327 g/mL × 1000 mL

Mass of 1 L solution = 932.7 g

Mass of solute:

Mass of 1 L = number of moles × molar mass

Mass = 5.73 mol × 46.068 g/mol

Mass = 263.97 g

Mass of solvent:

Mass of solvent = mass of solution - mass of solute

Mass of solvent = 932.7 g - 263.97 g

Mass of solvent = 668.73 g

In Kg = 668.73 /1000 = 0.6687 Kg

Molality:

Molality = number of moles of solute / mass of solvent in Kg

Molality = 5.73 mol / 0.6687 Kg

Molality = 8.57 m

4 0

2 years ago

¿Cuál de las siguientes reacciones se encuentra CORRECTAMENTE balanceada?

Svetach [21]

Answer:

opción c es la respuesta correcta espero que te ayude

4 0

3 years ago