1) D = 13.6 g / mL
2)ethyl alcohol weighs 158g
3)ρ
_copper = 8.9 g 
Explanation:
1)
D = m / V
=306.0 g / 22.5 mL
D= 13.6 g / mL
2)
density = mass / volume
mass = density × volume
=0.789g /ml × 200.0 ml
M=158g
Ethyl alcohol weighs 158g
3)
ρ (density) = Mass / Volume
ρ
_copper = 1896 g / 8.4cm × 5.5cm × 4.6cm
= 1896g / 212.5 
ρ
_copper=8.9 g 
Answer:
T₂ = 392 K
Explanation:
Given that,
Initial volume of the hot air balloon, V₁ = 55500 m³
Initial temperature, T₁ = 21°C = 294 K
Final volume, V₂ = 74000 m³
We need to find the final temperature inside the balloon. The relation between the temperature and volume is given by charles law i.e.

Where
T₂ is the final temperature
So,

So, the new temperature is 392 K.
Answer:
2) 0.4 mol
Explanation:
Step 1: Given data
- Volume of the solution (V): 500 mL
- Molar concentration of the solution (M): 0.8 M = 0.8 mol/L
Step 2: Convert "V" to L
We will use the conversion factor 1 L = 1000 mL.
500 mL × 1 L/1000 mL = 0.500 L
Step 3: Calculate the moles of KBr (solute)
The molarity is the quotient between the moles of solute (n) and the liters of solution.
M = n/V
n = M × V
n = 0.8 mol/L × 0.500 L = 0.4 mol
Answer:
91383 J
Explanation:
The equation of the reaction can be represented as:
------>
Given that:
The standard enthalpy of formation of NO(g) is 91.3 kJ⋅mol−1 at 298.15 K.
The equation below shown the reaction between the enthalpy of reaction at a particular temperature to another.
= 
where:
= enthalpy of reaction
= the difference in the heat capacities of the products and the reactants.
∴
=

= ![1(91300 J.mol^{-1} ) +\int\limits^{435}_{298.15} [{(29.86)-\frac{1}{2}(29.38)-\frac{1}{2}29.13}]J.K^{-1}.mol^{-1} \, dT'](https://tex.z-dn.net/?f=1%2891300%20J.mol%5E%7B-1%7D%20%29%20%2B%5Cint%5Climits%5E%7B435%7D_%7B298.15%7D%20%5B%7B%2829.86%29-%5Cfrac%7B1%7D%7B2%7D%2829.38%29-%5Cfrac%7B1%7D%7B2%7D29.13%7D%5DJ.K%5E%7B-1%7D.mol%5E%7B-1%7D%20%5C%2C%20dT%27)
= 91300 J + (0.605 J.K⁻¹)(435-298.15)K
= 91382.79 J
≅ 91383 J