Answer:
2 atoms
Explanation:
There are 2 atoms in element NaCl. This is because there is 1 atom of Na (sodium) and 1 atom of Cl (chlorine) in each NaCl molecule. Elements by themselves do not have a "number of atoms"- if you're talking about the atomic number, it's the number of protons (or electrons in a neutral atom) of an element.
Answer:
- Question 19: the three are molecular compounds.
Explanation:
<em>Question 19.</em>
All of them are the combination of two kinds of different atoms in fixed proportions.
- C₂H₄: two carbon atoms per four hydrogen atoms
- HF: one hydrogen atom per one fluorine atom
- H₂O₂: two hydrogen atoms per two oxygent atoms
Thus, they all meet the definition of compund: a pure substance formed by two or more different elements with a definite composition.
Molecular compounds are formed by covalent bonds and ionic compounds are formed by ionic bonds.
Two non-metal elements, like H-F, C - C, C - H, H-O, H - H, and O - O will share electrons forming covalent bonds to complete their valence shell. Thus, the three compounds are molecular and not ionic.
<em>Question 20. </em>Formula of copper(II) sulfate hydrate with 36.0% water.
Copper(II) sulfate is CuSO₄. Its molar mass is 159.609g/mol
Water is H₂O. Its molar mass is 18.015g/mol
Calling x the number of water molecules in the hydrate, the percentage of water is:

From which we can solve for x:

Thus, there are 5 molecules of water per each unit of CuSO₄, and the formula is:
We know that density is a measure of mass per unit of volume:
Density = Mass / Volume
Therefore, we can calculate for the mass
Mass = Density * Volume
if the density of water is 1 g/cm^3:
Mass = Density * Volume
= (1 g/cm^3) * 94.60 cm^3
= 94.60 g
:o really? thank you so much!
Given the Planck's constant and the speed of light, the energy of the ultraviolet light with a frequency of 9.58×10¹⁴ Hz is 6.35×10¯¹⁹ J (Option C)
<h3>Data obtained from the question </h3>
- Planck's constant (h) = 6.626×10¯³⁴ Js
- Speed of light (v) = 3×10⁸ m/s
- Frequency (f) = 9.58×10¹⁴ Hz
- Energy (E) =?
<h3>How to determine the energy </h3>
The energy of the ultraviolet light can be obtained as follow:
E = hf
E = 6.626×10¯³⁴ × 9.58×10¹⁴
E = 6.35×10¯¹⁹ J
Learn more about energy:
brainly.com/question/10703928