There are several differences between<span> a </span>physical and chemical change<span> in matter or substances. A </span>physical change<span> in a substance doesn't </span>change<span> what the substance is. In a </span>chemical change<span> where there is a </span>chemical<span> reaction, a new substance is formed and energy is either given off or absorbed.</span>
Answer:
True
Explanation:
The vertical columns on the periodic table are called groups or families because of their similar chemical behavior. All the members of a family of elements have the same number of valence electrons and similar chemical properties. The horizontal rows on the periodic table are called periods.
<span>1s2, 2s2, 2p6, 3s2, 3p6, 3d5</span>
Answer:
True
Explanation:
The speed that electromagnetic waves will travel within any medium is the same as those without a medium. The speed of electromagnetic wave is a constant and does not depend on the material of the medium.
- Electromagnetic waves are waves that do not require a material medium for their propagation.
- They are able to pass through vacuums and mediums with particles at constant speed.
- It is mechanical waves whose speed is medium dependent.
- Mechanical waves have varying speed based on the mediums they move through.
Answer:
40 g NaOH
Step-by-step explanation:x
To make 500 mL of a 2 mol·L⁻¹ solution, the technician must measure the correct mass of NaOH.
Step 1. Calculate the <em>moles of NaOH
</em>
c = n/V Multiply both sides by V
n = Vc
c = 2 mol·L⁻¹
V =0.5 L
n = 0.5 × 2
n = 1 mol NaOH
Step 2. Calculate the <em>mass of NaOH
</em>
The molar mass of NaOH is 40.00 g/mol.
m = 1 × 40.00/1
m = <em>40 g NaOH
</em>
The technician must measure <em>40 g of NaOH</em>.
