Answer:
2)Both the salt dissolving and the evaporation of water are physical changes.
Explanation:
The two kinds of changes that has occurred are both physical changes.
Dissolution of a solute such as salt in water and evaporation of water from a solution are physical changes.
A physical change is one in which the physical property of matter is altered. Particularly the state and the form.
In many of these cases, the change is easily reversible.
Since this change is reversible in that we were able to collect the salt back, this is a physical change.
The reaction between zinc and hydrochloric acid is Zn + HCl = H2 + ZnCl2. It is a single replacement reaction where zinc metal displaces the hydrogen to form hydrogen gas and zinc chloride, a salt. Zinc reacts quickly with the acid to form bubbles of hydrogen.
Draw eight circles and nine more in a big circle = this represents your nucleus
draw eight electrons (since electrons = protons in neutral elements) outside of it (2 in one ring, then 6 in a second ring)
Answer:
chemicals symbols are used for abbreviating the name of the element/chemical while chemicals formulas tell you how much of each element are in each chemical atom
Explanation:
The mass in grams of each of the following using dimensional analysis is:
- 6.02 x 10²³ atoms of Mg = 12g of Mg
- 3.01 x 10²³ formula units of CaCl2 = 55.5g of CaCl2
- 12.4 x 10¹⁵ molecules of formaldehyde (CH2O) = 0.000000618g of formaldehyde
<h3>How to calculate mass?</h3>
The mass of a substance can be calculated in different ways depending on whether molecules or moles are given.
First, we need to convert atoms/formula units/molecules to moles as follows:
- 6.02 × 10²³ ÷ 6.02 × 10²³ = 1 mole of Mg
- 3.01 x 10²³ ÷ 6.02 × 10²³ = 0.5 moles of CaCl2
- 12.4 x 10¹⁵ ÷ 6.02 × 10²³ = 2.06 × 10-⁸ moles of formaldehyde
Next, we convert each mole value to mass as follows:
- 1 mole of Mg = 1 × 12 = 12g of Mg
- 0.5 moles of CaCl2 = 0.5 × 111 = 55.5g of CaCl2
- 2.06 × 10-⁸ moles of CH2O = 0.000000618g of formaldehyde
Learn more about mass at: brainly.com/question/19694949
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