A beaker of black powder can be a mixture with different substances (i.e gunpowder: a mixture of sulfur, charcoal, etc.), an element which can probably be carbon (known as black), and a compound as well which can be potassium nitrate. Hence, the answer is D.
Chlorine has a smaller atomic size.
Explanation: As you move towards right of the periodic table, the atomic size decreases. This is because the number of protons is increasing towards the right of the periodic table, which applies a greater inward force on the electrons. that is why the elements on the right of the periodic table have a smaller atomic size when compared to the elements on the left. Since chlorine is on the right side of aluminium, it has a smaller atomic size.
Answer:
\large \boxed{\textbf{609 kJ}}
Explanation:
The formula for the heat absorbed is
q = mCΔT
Data:
m = 2.07 kg
T₁ = 23 °C
T₂ = 191 °C
C = 1.75 J·°C⁻¹g⁻¹
Calculations:
1. Convert kilograms to grams
2.07 kg = 2070 g
2. Calculate ΔT
ΔT = T₂ - T₁ = 191 - 23 = 168 °C
3. Calculate q
Answer:
38
Explanation:
Symbol: Sr
Atomic mass: 87.62 u
Electrons per shell: 2,8,18,8,2
Atomic number: 38
Electron configuration: [Kr] 5s2
Van der Waals radius: 255 pm
Valence electrons: two
