Answer: The closeness, arrangement and motion of the particles in a substance change when it changes state. Materials are a store of internal energy , due to the motion of particles and the chemical bonds between them. When a substance is heated, its internal energy increases: the movement of its particles increases.
Explanation:
Option 1/A (It is the first one)
Answer:
0.19 g
Explanation:
Step 1: Given data
Volume of hydrogen at standard temperature and pressure (STP): 2.1 L
Step 2: Calculate the moles corresponding to 2.1 L of hydrogen at STP
At STP (273.15 K and 1 atm), 1 mole of hydrogen has a volume of 22.4 L if we treat it as an ideal gas.
2.1 L × 1 mol/22.4 L = 0.094 mol
Step 3: Calculate the mass corresponding to 0.094 moles of hydrogen
The molar mass of hydrogen is 2.02 g/mol.
0.094 mol × 2.02 g/mol = 0.19 g
Answer:
All living things are made up of cells.
cells are the basic unit of structure and function of ll living things.
All cells are come from other cells.
Explanation:
The cell theory is historic scientific theory and is universally accepted. This theory was given by Robert Hook in 1665. According to this theory all living things are made up cells.
Cell:
Cell is the smallest unit of life and it is building block of life.
This theory consist of following points:
All living things are made up of cells.
Cells are the basic unit of structure and function of ll living things.
All cells are come from other cells. Which means that cells are originated from pre-existing cells.
The other given options:
Cells comes from nonliving matter.
Cells make up most organisms bu not all.
These are two are not the postulate of cell theory because all living organisms are made of cells.
Answer:
frequency = 0.47×10⁴ Hz
Explanation:
Given data:
Wavelength of wave = 6.4× 10⁴ m
Frequency of wave = ?
Solution:
Formula:
Speed of wave = wavelength × frequency
Speed of wave = 3 × 10⁸ m/s
Now we will put the values in formula.
3 × 10⁸ m/s = 6.4× 10⁴ m × frequency
frequency = 3 × 10⁸ m/s / 6.4× 10⁴ m
frequency = 0.47×10⁴ /s
s⁻¹ = Hz
frequency = 0.47×10⁴ Hz
Thus the wave with wavelength of 6.4× 10⁴ m have 0.47×10⁴ Hz frequency.
