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Elodia [21]
2 years ago
7

Which statement about the periodic table is true?

Chemistry
1 answer:
dedylja [7]2 years ago
8 0

Answer

Two different elements have similar chemical properties when they have the same number of valence electrons in their outermost energy level. ... Elements in the same column of the Periodic Table have the same number of valence electrons – that's why they have similar chemical properties.

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what tool do you have to use to precise amount of water? A meter stick B stopwatch C balance D graduated cylinder E beaker F the
Serhud [2]

Answer:

graduated cylinder

Explanation:

It shows exact volume very precisely.

8 0
3 years ago
A tank of 0.1m3 volume contains air at 25∘C and 101.33 kPa. The tank is connected to a compressed-air line which supplies air at
Dmitriy789 [7]

Answer:

Amount of Energy = 23,467.9278J

Explanation:

Given

Cv = 5/2R

Cp = 7/2R wjere R = Boltzmann constant = 8.314

The energy balance in the tank is given as

∆U = Q + W

According to the first law of thermodynamics

In the question, it can be observed that the volume of the reactor is unaltered

So, dV = W = 0.

The Internal energy to keep the tank's constant temperature is given as

∆U = Cv((45°C) - (25°C))

∆U = Cv((45 + 273) - (25 + 273))

∆U = Cv(20)

∆U = 5/2 * 8.314 * 20

∆U = 415.7 J/mol

Before calculating the heat loss of the tank, we must first calculate the amount of moles of gas that entered the tank where P1 = 101.33 kPa

The Initial mole is calculated as

(P * V)/(R * T)

Where P = P1 = 101.33kPa = 101330Pa

V = Volume of Tank = 0.1m³

R = 8.314J/molK

T = Initial Temperature = 25 + 273 = 298K

So, n = (101330 * 0.1)/(8.314*298)

n = 4.089891232222

n = 4.089

Then we Calculate the final moles at P2 = 1500kPa = 1500000Pa

V = Volume of Tank = 0.1m³

R = 8.314J/molK

T = Initial Temperature = 25 + 273 = 298K

n = (1500000 * 0.1)/(8.314*298)

n = 60.54314465936812

n = 60.543

So, tue moles that entered the tank is ∆n

∆n = 60.543 - 4.089

∆n = 56.454

Amount of Energy is then calculated as:(∆n)(U)

Q = 415.7 * 56.454

Q = 23,467.9278J

3 0
3 years ago
50.0 grams of KCl is dissolved in water to make a 4.00 L
xeze [42]

Answer:0.1677M

Explanation:

Molarity=moles/volume

Number of moles =mass/molar mass

Once you get the number of moles, you apply it to the molarity formula.

8 0
3 years ago
KOH (aq) + HNO(little3) (aq) = KNO(little 3) (aq) + H20 (1)
Yuki888 [10]

The reaction already balanced

<h3>Further explanation  </h3>

Equalization of chemical reactions can be done using variables. Steps in equalizing the reaction equation:  

• 1. gives a coefficient on substances involved in the equation of reaction such as a, b, or c, etc.  

• 2. make an equation based on the similarity of the number of atoms where the number of atoms = coefficient × index (subscript) between reactant and product  

• 3. Select the coefficient of the substance with the most complex chemical formula equal to 1  

For gas combustion reaction which is a reaction of hydrocarbons with oxygen produces CO₂ and H₂O (water vapor). can use steps:  

Balancing C, H and the last O  

Reaction

KOH (aq) + HNO₃ (aq) ⇒ KNO₃ (aq) + H₂0 (l)

  • give coefficient

aKOH (aq) + bHNO₃ (aq) ⇒ KNO₃ (aq) + cH₂0 (l)

K : left = a, right = 1⇒a=1

N : left = b, right =1, b=1

H: left = a, right a+b=2c⇒1+1=2c⇒2=2c⇒c=1

KOH (aq) + HNO₃ (aq) ⇒ KNO₃ (aq) + H₂0 (l)⇒ already balanced

5 0
3 years ago
1. Energy is expended when a force moves matter across a distance. True/False
Novosadov [1.4K]
1. True
2. True
3. False
4. True
5. True

3. Heat can be thought of as the movement of particles (molecules etc). The faster they move the hotter things are. Energy of movement is called kinetic energy. Temperature is a measure of the average kinetic energy of the particles, while thermal energy is the total kinetic energy of the particles.
8 0
3 years ago
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