Answer:
Galileo Galilei
What launched the era of modern science in the 17th century? Modern science began in the 17th century, when the Italian physicist Galileo Galilei revived the Copernican view.
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Explanation:
Lead have:
82 electrons
82 protons
125 neutrons
Explanation:
The number of electrons and protons are given by the atomic number of the element.
Lead have 82 electrons and 82 protons.
The number of neutrons are given by the difference between the mass number and atomic number.
For lead number of neutrons = 207 - 82 = 125.
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particles in the atom
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Answer:
Na₂₆F₁₁
Explanation:
We find the moles of the substance assuming 100 g of the substance is present. Why do we take 100 g? Because then the percent of sodium/fluorine, would be the g of sodium/fluorine respectively:
74.186 g Sodium | 1 mol Sodium/23 g => 3.2255 mol Na
25.814 g Fluorine | 1 mol Fluorine/19 g => 1.3586 mol F
Divide each by smallest number of moles:
3.2255/1.3586 = 2.37
1.3586/1.3586 = 1
Multiply by common number to get a smallest whole number:
2.37*11 = 26,
1*11 = 11
The empirical formula is Na₂₆F₁₁
Answer:
Adding a catalyst - More collisions every second and more collisions with enough energy to break bonds.
Increase in pressure - more collisions every second
Increase in temperature - more collisions every second with enough energy to break bonds
Explanation:
According to the collision theory, chemical reaction occurs as a result of collision between reacting particles. Only particles that possess energy above the activation energy of the reaction can collide and result in product formation. Collision of particles having energy less than the activation energy merely result in elastic collisions.
Adding a catalyst lowers the activation energy of the reaction. If the activation energy is lowered, more reactants collide and more of those collisions now have enough energy to break bonds.
When the temperature is increased, the particles become more energetic hence more collisions with energy to break bonds occur.
Increase in pressure brings the reactant particles into close proximity hence more collisions occur.
