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The modern periodic table is arranged in order of increasing. true or false

qaws [65]

Answer:

Increasing atomic number - True

Explanation:

The modern table is based on Mendeleev’s table, except the modern table arranges the elements by increasing atomic number instead of atomic mass.

The Atomic number is the number of protons in an atom, and this number is unique for each element. For example, Hydrogen has an atomic number of 1, Calcium has an atomic number of 20.

In the modern periodic table the elements are further arranged into:

- rows, called periods, in order of increasing atomic number. Elements in the same periods have the same number of shells.

- vertical columns, called groups, where the elements have similar properties. Elements in the same group has the same number of valency (outermost number of electrons)

4 0

3 years ago

What is the molality of a solution of water and kcl if the freezing point of the solution is –3mc030-1.jpgc?

Natasha_Volkova [10]

We will use the expression for freezing point depression ∆Tf
∆Tf = i Kf m
Since we know that the freezing point of water is 0 degree Celsius, temperature change ∆Tf is
∆Tf = 0C - (-3°C) = 3°C
and the van't Hoff Factor i is approximately equal to 2 since one molecule of KCl in aqueous solution will produce one K+ ion and one Cl- ion:
KCl → K+ + Cl-
Therefore, the molality m of the solution can be calculated as
3 = 2 * 1.86 * m
m = 3 / (2 * 1.86)
m = 0.80 molal

4 0

3 years ago

What is the name of P517

saul85 [17]

Answer:

Ryobi P517 18V Lithium Ion Cordless Brushless 2,900 SPM Reciprocating Saw w/ Anti-Vibration Handle and Tool-Less Blade Changing

Explanation:

8 0

3 years ago

An element has an atomic number of 30. How many protons and electrons are in a neutral atom of the element? A. 30 protons, 30 el

Minchanka [31]

Atomic number shows the number of protons in an atom's nucleus. If the atomic number is 30, then it has 30 protons. The question says it is neutral, so it must have the same amount of protons and electrons.

A is the correct answer based on this.

7 0

3 years ago

If 156.06 g of propane, C3H8, is burned in excess oxygen, how many grams of water are formed? C3H8 + O2 → CO2 + H2O Select one:

Nastasia [14]

Answer:

The correct option is;

a. 255.0 g

Explanation:

The given information are;

Mass of propane, C₃H₈ in the combustion reaction = 156.06 g

The equation of the combustion reaction is C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

From the balanced chemical equation of the reaction, we have;

One mole of propane, C₃H₈ reacts with five moles oxygen gas, O₂, to form three moles of carbon dioxide, CO₂, and four moles of water, H₂O

The molar mass of propane gas = 44.1 g/mol

The number of moles, n, of propane gas = Mass of propane gas/(Molar mass of propane gas) = 156.06/44.1 = 3.54 moles

Given that one mole of propane gas produces 4 moles of water molecule (steam) H₂O, 3.54 moles of propane gas will produce 4×3.54 = 14.16 moles of (steam) H₂O

The mass of one mole of H₂O = 18.01528 g/mol

The mass of 14.16 moles of H₂O = 14.16 × 18.01528 = 255.0 g

The mass of H₂O produced = 255.0 g

3 0

3 years ago

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