Answer:
0.4444 g/cm³ ≅ 0.44 g/cm³ (2 significant figures).
Explanation:
<em>d = m/V,</em>
where, d is the density of the material (g/cm³).
m is the mass of the material (m = 28 g).
V is the volume of the material (V = 63.0 cm³).
<em>∴ d = m/V </em>= (28 g)/(63.0 cm³) = <em>0.4444 g/cm³ ≅ 0.44 g/cm³ (2 significant figures).</em>
We can use the ideal gas law equation to find the volume of the gas.
PV = nRT
P - pressure - 400 kPa
V - volume
n - number of moles - 4.00 mol
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature - 300.0 K
substituting these values in the equation
400 000 Pa x V = 4.00 mol x 8.314 Jmol⁻¹K⁻¹ x 300.0 K
V = 24.9 dm³
Volume is 24.9 dm³
Answer: D, splitting water into hydrogen and oxygen is a chemical change.
The correct answer is the one in the middle. Mixing food coloring and water
M=260 g
M=414.215 g/mol
n=m/M
n=260 g / 414.215 g/mol = 0.6277 mol