To calculate the mass, go from atoms to moles and moles to grams:
Atoms ........ Moles.......... Grams
From atoms to moles, use the Avogadro’s no. which is 6.022 x
10^23 and from moles to grams use atomic mass of Pt that is 195.08g.
So, 4.91 x 10^21 Pt atoms x (1 mole Pt / 6.022x10^23 Pt atoms) x (195.08g Pt
/ 1 mole Pt) = 1.59g Pt
Mass of 4.91 x 10^21 Pt atoms = 1.59g Pt
Answer:

Explanation:
The pressure is constant, so, to calculate the volume, we can use Charles' Law:
\dfrac{V_{1}}{T_{1}} = \dfrac{V_{2}}{T_{2}}
Data:
V₁ = ?; T₁ = 450 K
V₂ = 103.4 L; T₂ = 284.9 K
Calculation:

Answer:
im pretty sure its A, if not so sorry!!
Explanation:
Answer:
High conductivity
Explanation:
Metals exhibit high conductivity due to the mobility of valence electrons.
Answer:
The correct option is;
D. (2)(56 g)
Explanation:
MgCl₂ + 2KOH → Mg(OH)₂ + 2KCl
From the balanced chemical reaction equation, we have;
One mole of MgCl₂ reacts with two moles of KOH to produce one mole of Mg(OH)₂ and 2 moles of KCl
Therefore, the number of moles of KOH that react with one mole of KCl = 2 moles
The mass, m, of the two moles of KOH = Number of moles of KOH × Molar mass of KOH
The molar mass of KOH = 56.1056 g/mol
∴ The mass, m, of the two moles of KOH = 2 moles × 56.1056 g/mol = 112.2112 grams
The amount in grams of KOH that react with one mole of MgCl₂ = 112.2112 grams ≈ 112 grams = (2)(56 g).