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3 years ago

6. Identify the number of neutrons in one atom of silicon with an isotopic mass number of 28 amu.

Chemistry

1 answer:

Sholpan [36]3 years ago

5 0

Explanation:

The number of neutrons in one atom of silicon with an isotopic mass number of 28amu is 14.

An atom is made up three fundamental sub-atomic particles which are:

Protons, neutron and electrons

Protons are the positively charged particles in an atom

Neutrons do not carry any charges

Electrons are the negatively charged particles.

In the nucleus of an atom, both protons and neutrons can be found. They are the massive particle in an atom.

The mass number of an atom = number of protons + number of neutrons

Number of neutrons = mass number - number of protons.

From the periodic table, we know that silicon has an atomic number of 14.

The atomic number is the number of protons in an atom:

Number of neutrons = 28 - 14 = 14amu

In the atom, we will have 14amu of neutrons in a silicon atom.

learn more:

Number of neutrons brainly.com/question/2757829

#learnwithBrainly

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The time required for one-half of the atoms from a sample of a radioactive substance to decay is called its _____.

Orlov [11]

A.) half - life of a radioactive substance is defined as the time during which concentration of the substance becomes half the initial value.

8 0

3 years ago

Read 2 more answers

Need help with 14 and 16 pls asap!! this is my friends test and im taking it tomorrow!!

marin [14]

Answer:

Q14: 17,140 g = 17.14 kg.

Q16: 504 J.

Explanation:

Q14:

To solve this problem, we can use the relation:

Q = m.c.ΔT,

where, Q is the amount of heat absorbed by ice (Q = 3600 x 10³ J).

m is the mass of the ice (m = ??? g).

c is the specific heat of the ice (c of ice = 2.1 J/g.°C).

ΔT is the difference between the initial and final temperature (ΔT = final T - initial T = 100.0°C - 0.0°C = 100.0°C).

∵ Q = m.c.ΔT

∴ (3600 x 10³ J) = m.(2.1 J/g.°C).(100.0°C)

∴ m = (3600 x 10³ J)/(2.1 J/g.°C).(100.0°C) = 17,140 g = 17.14 kg.

Q16:

To solve this problem, we can use the relation:

Q = m.c.ΔT,

where, Q is the amount of heat absorbed by ice (Q = ??? J).

m is the mass of the ice (m = 12.0 g).

c is the specific heat of the ice (c of ice = 2.1 J/g.°C).

ΔT is the difference between the initial and final temperature (ΔT = final T - initial T = 0.0°C - (-20.0°C) = 20.0°C).

∴ Q = m.c.ΔT = (12.0 g)(2.1 J/g.°C)(20.0°C) = 504 J.

6 0

3 years ago

A sample of 4.0 L of nitrogen, at 1.2 atmospheres, is transferred to a 12 L container.

Zielflug [23.3K]

Answer:

The pressure will be 0.4 atm.

Explanation:

The gas laws are a set of chemical and physical laws that allow determining the behavior of gases in a closed system. The parameters evaluated in these laws are pressure, volume, temperature and moles.

As the volume increases, the gas particles (atoms or molecules) take longer to reach the walls of the container and therefore collide with them less times per unit of time. This means that the pressure will be lower because it represents the frequency of collisions of the gas against the walls. In this way pressure and volume are related, determining Boyle's law which says:

"The volume occupied by a certain gaseous mass at constant temperature is inversely proportional to pressure"

Boyle's law is expressed mathematically as:

P*V= k

If you initially have the gas at a volume V1 and press P1, when the conditions change to a volume V2 and pressure P2, the following is satisfied:

P1*V1= P2*V2

In this case:

P1= 1.2 atm
V1= 4 L
P2= ?
V2= 12 L

Replacing:

1.2 atm* 4 L= P2* 12 L

Solving:

$P2=\frac{1.2 atm*4 L}{12 L}$

P2= 0.4 atm

The pressure will be 0.4 atm.

7 0

3 years ago

8. The standard enthalpy of formation of RbF(s) is –557.7kJ/mol and the standard enthalpy of formation of RbF(aq, 1 m) is –583.8

garri49 [273]

Explanation:

Given

The enthalpy of formation of RbF (s) is –557.7kJ/mol

The standard enthalpy of formation of RbF (aq, 1 m) is –583.8 kJ/mol

The enthalpy of solution of RbF = Enthalpy of RbF (aq) - Enthalpy of formation of RbF (s)

= -583.8 - (-557.7) kJ/mol

= -26.1 kJ/mol

The enthalpy is negative which means that the temperature will rise when RbF is dissolved.

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3 years ago

Identify an element as a metal or a non-metal according to its position in the Periodic Table

Anestetic [448]

Answer:

Metals on the left of the Periodic Table.

Non-Metals on the top-right, plus Hydrogen.

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3 years ago