Answer:
Mass = 208.26 g
Explanation:
Given data:
Volume of water = 40.0 mL
Volume of water + copper = 63.4 mL
Volume of copper = ?
Density of copper = 8.9 g/cm³
Mass of copper = ?
Solution:
Volume of copper:
Volume of copper = (Volume of water + copper ) - Volume of water
Volume of copper = 63.4 mL - 40.0 mL
Volume of copper = 23.4 mL
Mass of copper:
density = mass/volume
8.9 g/cm³ = mass/23.4 mL
cm³ = mL
Mass = 8.9 g/mL × 23.4 mL
Mass = 208.26 g
Gravitational force -an attractive force that exists between all objects with mass; an object with mass attracts another object with mass; the magnitude of the force is directly proportional to the masses of the two objects and inversely proportional to the square of the distance between the two objects.
Answer:
The reaction of one mole of oxygen (O2) releases 445 kJ of energy.
Explanation:
Firstly, the reaction is exothermic since the sign of enthalpy change ΔH is negative.
The balanced equation: CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l): ΔH = −890 kJ,
Shows that 1 mole of CH₄ react with 2 moles of oxygen and releases 890 kJ.
So, every choice says that absorb is wrong (choice 1& 3).
Choice no. 4 is wrong since it says that 2 moles of methane releases 890 kJ, because only one mole release this amount of energy.
So, the right choice is The reaction of one mole of oxygen (O2) releases 445 kJ of energy.
Wave speed = frequency x wavelength
= 50 x 0.1
= 5 m/s
Hope this helps!
