Answer: The element shown in the image is Helium (He).
Explanation: We are given a image of an atom having protons, neutrons and electrons.
Number of protons as shown in image = 2
Number of neutrons as shown in image = 2
Number of electron as shown in image = 2
Atomic number = Number of protons = Number of electrons
Atomic number of the element = 2
Atomic Mass = Number of protons + Number of neutrons
Atomic mass = 2 + 2 = 4
The element having Atomic number = 2 and mass number = 4 is Helium.
Element = 
Answer:
Number of moles = 0.0005 mol.
Explanation:
Given data:
pH = 3
Volume of solution = 500 mL
Number of moles = ?
Solution:
HCl dissociate to gives H⁺ and Cl⁻
HCl → H⁺ + Cl⁻
It is known that,
pH = -log [H⁺]
3 = -log [H⁺]
[H⁺] = 10⁻³ M
[H⁺] = 0.001 M
Number of moles of HCl:
Molarity = number of moles / Volume in litter
Number of moles = Molarity × Volume in litter
Number of moles = 0.001 mol/L × 0.5 L
Number of moles = 0.0005 mol
Answer:
1.07 g Ba
Explanation:
Hello there!
In this case, according to the definition of the Avogadro's number and the molar mass, it is possible to say that 6.022x10^{23} atoms of barium equal one mole, and at the same time, 1 mole equals 137.327 grams of this element; thus, it is possible to say that 6.022x10^{23} atoms of barium have a mass of 137.327 grams; therefore, it i possible for us to calculate the required mass in grams as shown below:
Best regards!
Im pretty sure the answer is <span> 0.01218859659g
not 100% sure tho so please consult someone else b4 answering
i hope this helps!!</span>
