Answer:
Metal
Element: Calcium
Valency: 2
Explanation:
To find the element, let's use the periodic table. (Look below)
We already went past 3 shells, just need the 2 electrons after it.
Just skip to the 4th row and count 2 to the right
We end up at Calcium.
Calcium is a metal and we're also on the alkaline earth metals column.
Calcium will need to lose 2 electrons to reach stability, so the valency is 2.
Answer:
endothermic
Explanation:
the negative sign of the heat indicates that heat is being drawn into the system, thus endothermic
Answer:
This reaction is characteristic to metal carbonates, which decompose when heated to form the oxide of the metal and carbon dioxide gas.
Explanation:
Just did it...
<h3>Answer:</h3>
2.55 × 10²² Na Atoms
<h3>Solution:</h3>
Data Given:
M.Mass of Na = 23 g.mol⁻¹
Mass of Na = 973 mg = 0.973 g
# of Na Atoms = ??
Step 1: Calculate Moles of Na as:
Moles = Mass ÷ M.Mass
Moles = 0.973 g ÷ 23 g.mol⁻¹
Moles = 0.0423 mol
Step 2: Calculate No, of Na Atoms as:
As 1 mole of sodium atoms counts 6.022 × 10²³ and equals exactly to the mass of 23 g. So, we can write,
Moles = No. of Na Atoms ÷ 6.022 × 10²³ Na Atoms.mol⁻¹
Solving for No. of Na Atoms,
No. of Na Atoms = Moles × 6.022 × 10²³ Na Atoms.mol⁻¹
No. of Na Atoms = 0.0423 mol × 6.022 × 10²³ Na Atoms.mol⁻¹
No. of Na Atoms = 2.55 × 10²² Na Atoms
<h3>Conclusion: </h3>
2.55 × 10²² sodium atoms are required to reach a total mass of 973 mg in a substance of pure sodium.
Answer:
A. The human body can break down complex carbohydrates into sugar molecules that provide energy.
Explanation:
Strings of glucose, form complex carbohydrates such as starch and glycogen. Glycogen which is a stored form of glucose in humans is a source of long-term energy, and a complex carbohydrate because glycogen can be converted to glucose-1-phosphate which can enter the glycolytic cycle to generate Adenosine triphosphate which is a unit of energy.
This stored form of energy can be slowly broken down to release energy when needed by the body. During exercise, for instance, glycogen can slowly release ATP needed for energy.
