Explanation:
Tc - 99 is technetium 99.
It is a radioactive element that decays spontaneously. It has a half-life of 211,000 years and decays to stable ruthenium.
- On the periodic table, it has an atomic number of 43;
Mass number = 99
Atomic number = number of protons = number of electrons in atom
Number of protons in Tc is 43
electron is 43
Mass number = number of protons + number of neutrons
Number of neutrons = mass number - number of protons = 99-43 = 56
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Atomic number brainly.com/question/2057656
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Answer:
Box is made up of <em>copper</em>, because density is <em>8.96 g/cm³.</em>
Explanation:
Given data:
Volume of box = 17.63 cm³
Mass of box = 158 g
Which metal box is this = ?
Solution:
First we will calculate the density of box then we will compare it with the density value of given metals.
d = m/v
d = 158 g/ 17.63 cm³
d = 8.96 g/cm³
The calculated density is similar to the given density value of copper thus box is made up of copper.
Answer:
58.0 g of MgO
Explanation:
in a perfect world, 70 g, however we don't live in a perfect world
The equation of reaction
2Mg + O₂ --> 2MgO
first find which element is limiting:
35 g x 1 mol/24.3 g of Mg x 2 mol of MgO/ 2 mole of Mg = 1.44 moles of MgO
35 g x 1 mol/32g of Mg x 2 mol of MgO/ 1 mole of O₂ = 2.1875 moles of MgO
This means Mg is the limiting factor, so you will be using this moles to find grams of MgO
1.44 mols of MgO x 40.3 g of MgO/ 1 mol = 58.0 g of MgO
Answer:
The rock cycle and plate tectonics cause Earth's rocks to break down over time and they are recycled through natural processes.
Explanation:
Rock cycle(Attachment-1)
Answer:
Its a 50% chance of it happeing
Explanation:
