Tataattatataaggagahahah( to answer it)
9. A
10. C
Mass (g) / Volume (cm^3) = Density (g/cm^3)
60.4g/ 11.3 cm^3 = 5.35 g/cm^3
d= 5.35 g/cm^3
Answer:
4.4 g
Explanation:
Step 1: Write the balanced equation
Cu + 4 HNO₃ ⇒ Cu(NO₃)₂ + 2 NO₂ + 2 H₂O
Step 2: Calculate the moles corresponding to 3.2 L of NO₂ at STP
At standard temperature and pressure, 1 mole of NO₂ occupies 22.4 L.
3.2 L × 1 mol/22.4 L = 0.14 mol
Step 3: Calculate the moles of Cu needed to produce 0.14 moles of NO₂
The molar ratio of Cu to NO₂ is 1:2. The moles of Cu needed are 1/2 × 0.14 mol = 0.070 mol.
Step 4: Calculate the mass corresponding to 0.070 moles of Cu
The molar mass of Cu is 63.55 g/mol.
0.070 mol × 63.55 g/mol = 4.4 g
Answer:
Option C = 30 j
Explanation:
Given data:
mass of snowboard = 5 Kg
Initial speed = 2 m/s
final speed = 4 m/s
work done = ΔE= ?
ΔE= change in kinetic energy
Solution:
Formula:
K.E (initial) = 1/2 × mv²
K.E (initial) = 1/2 × 5 Kg . (2m/s)²
K.E (initial) = 1/2 × 20 Kg.m²/s²
K.E (initial) = 10 Kg.m²/s² or 10 J
Kg.m²/s² = J
K.E (finial) = 1/2 × mv²
K.E (finial) = 1/2 × 5 Kg . (4m/s)²
K.E (finial) = 1/2 × 5 Kg . 16 m²/s²
K.E (finial) = 1/2 × 80 Kg.m²/s²
K.E (finial) = 40 Kg.m²/s² or 40 J
work done = ΔE = K.E (finial) - K.E (initial)
work done = ΔE = 40 J - 10 J
work done = ΔE = 30 J
The answer is 18.02 grams
