Answer:
Dmitri Mendeleev=Russian chemist, Albert Ghiorso=American scientist
Explanation:
<h2>Nucleosynthesis.</h2>
Explanation:
A. the Big Bang occurred; the Big Crunch occurred
Nucleosynthesis is the process by which new atomic nucleus are formed from pre-existing protons and neutrons.
According to cosmic theories, the nucleosythesis began one minute after the occurrence of Big bang and will end with the big Crunch.
The Big bang theory describes all the processes by which the universe came into existence while the big crunch theory explains how universe will come to an end. A
Answer:
A change is called irreversible if it cannot be changed back again. In an irreversible change, new materials are always formed.
Explanation:
Answer:
1.55 × 10²⁴ atoms Xe
General Formulas and Concepts:
<u>Atomic Structure</u>
- Reading a Periodic Table
- Moles
- STP (Standard Conditions for Temperature and Pressure) = 22.4 L per mole at 1 atm, 273 K
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
<u>Stoichiometry</u>
- Using Dimensional Analysis
Explanation:
<u>Step 1: Define</u>
[Given] 57.5 L Xe at STP
[Solve] atoms Xe
<u>Step 2: Identify Conversions</u>
[STP] 22.4 L = 1 mol
Avogadro's Number
<u>Step 3: Convert</u>
- [DA] Set up:

- [DA] Divide/Multiply [Cancel out units]:

<u>Step 4: Check</u>
<em>Follow sig fig rules and round. We are given 3 sig figs.</em>
1.54583 × 10²⁴ atoms Xe ≈ 1.55 × 10²⁴ atoms Xe
Answer: The mass is 980.6g of Gold.
Explanation:
We begin by looking for the number of moles equivalent to 3.0 x 10^24 gold atoms.
Using the Avogadro's number,
6.02 x 10^23 atoms of gold make up 1 mole of gold.
3.0 x 10^24 atoms would make up: 1 / 6.02 x 10^23 x 3.0 x 10^24 = 4.98moles.
Now that we know the number of moles, we can then look for the mass using the formular:
Moles = mass/ molar mass
4.98 = mass / 196.9 (atomic mass of gold)
Making "mass" the subject of formula : mass = 4.98 x 196.9= 980.6g