The correct answer is C : energy level.
As you can see in the image of the periodic table presented below, periods are the horizontal columns of the periodic table.
Elements belonging to the same period have the same electron shell, the same number of orbits filled with electrons.
Elements of the same period have similar chemical and physical characteristics
Answer:
120g
Explanation:
Step 1:
We'll begin by writing the balanced equation for the reaction.
Sn + 2HF —> SnF2 + H2
Step 2:
Determination of the number of mole HF needed to react with 3 moles of Sn.
From the balanced equation above,
1 mole of Sn and reacted with 2 moles of HF.
Therefore, 3 moles Sn will react with = 3 x 2 = 6 moles of HF.
Step 3:
Conversion of 6 moles of HF to grams.
Number of mole HF = 6 moles
Molar Mass of HF = 1 + 19 = 20g/mol
Mass of HF =..?
Mass = number of mole x molar Mass
Mass of HF = 6 x 20
Mass of HF = 120g
Therefore, 120g of HF is needed to react with 3 moles of Sn.
Answer: The given statement is false.
Explanation:
Precipitation reaction is defined as the chemical reaction in which two aqueous solution upon mixing together results in the formation of an insoluble solid.
For example,
Here AgCl is present in solid state so, it is the precipitate.
But it is not necessarily true that two aqueous solutions will always result in the formation of a precipitate.
For example,
Hence, we can conclude that the statement precipitation reactions always occur when two aqueous solutions are mixed, is false.
Cardenolides, with the chemical formula CH₁₈C₂₀H₁₅CHCO₂ have (D) 23 carbon atoms, 34 hydrogen atoms, and 2 oxygen atoms.
Milkweed contains a poison known as cardenolides. The chemical formula for cardenolides CH₁₈C₂₀H₁₅CHCO₂.
The subscripts in the formula represent the atomicities, that is the number of atoms of each element in each part of the formula.
We can calculate the total number of atoms of each element by adding its atomicities.
<h3>Carbon atoms</h3>
<h3>Hydrogen atoms</h3>
<h3>Oxygen atoms</h3>
Cardenolides, with the chemical formula CH₁₈C₂₀H₁₅CHCO₂ have (D) 23 carbon atoms, 34 hydrogen atoms, and 2 oxygen atoms
Learn more: brainly.com/question/13348838