Answer:
b
Explanation:
Plants need carbon dioxide and let out oxygen
c. table salt is a metalloid with properties of both reactants
Answer:
3.2 L
Explanation:
Given data:
Mass of oxygen = 3.760 g
Pressure of gas = 88.4 Kpa (88.4×1000 = 88400 Nm⁻²)
Temperature = 19°C (19+273.15 = 292.15 K)
R = 8.314 Nm K⁻¹ mol⁻¹
Volume occupied = ?
Solution:
Number of moles of oxygen:
Number of moles = mass/ molar mass
Number of moles = 3.760 g/ 32 g/mol
Number of moles = 0.12 mol
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant
T = temperature in kelvin
V = nRT/P
V = 0.12 mol × 8.314 Nm K⁻¹ mol⁻¹ × 292.15 K /88400 Nm⁻²
V = 291.472 Nm /88400 Nm⁻²
V = 0.0032 m³
m³ to L:
V = 0.0032×1000 = 3.2 L
Answer:
8.0 × 10²¹ atoms contain 1.33 × 10⁻² moles.
Explanation:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
Given data:
Number of atoms = 8.0 × 10²¹ atoms
Number of moles = ?
Solution:
One mole of Cu = 6.022 × 10²³ atoms
For 8.0 × 10²¹ atoms:
(1 mol / 6.022 × 10²³ atoms)×8.0 × 10²¹ atoms
1.33 × 10⁻² moles
So, 8.0 × 10²¹ atoms contain 1.33 × 10⁻² moles.
