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timama [110]
3 years ago
11

How do scientists measure the idea of time so long ago?

Chemistry
1 answer:
aleksklad [387]3 years ago
4 0

The Ancient Egyptians used simple sundials and divided days into smaller parts, and it has been suggested that as early as 1,500BC, they divided the interval between sunrise and sunset into 12 parts. ... Known as a clepsydra, it uses a flow of water to measure time.

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How many grams of H2O are needed to produce 150 g of Mg(OH)2? (Molar mass: H2O = 18.02 g/mol; Mg(OH)2 = 58.33 g/mol )
Nuetrik [128]

Answer:

92.6

Explanation:

6 mol x 18.02 g of H2o --> 3 mol x 58.33 g  Mg(OH)2

108.12 g of h2o --> 174.99 of Mg(OH)2

g of H2O is 150 g of Mg(OH)2

150g x 108.12g / 174.99 =

92.67

7 0
3 years ago
Which of the following statements is true of combustion reactions?
enot [183]

Gasoline contains C and H atoms. During combustion, the carbon (C) from the fuel combines with oxygen (O2) from the air to produce carbon dioxide (CO2).
2 C8H18 + 25 O2 → 16 CO2 + 18 H2O.

Combustion reactions release large amounts of heat. They have negative enthalpy. A negative enthalpy represents an exothermic reaction, releasing heat. This reaction is spontaneous and exothermic, since we can obtain energy from the reaction; the ΔG (free energy) is negative (So 1 is true).

ΔG < 0, so the free energy of the system decreases with the reaction. Remember that when there is a negative ΔG the reaction goes from higher free energy to lower free energy, like in this case.

8 0
3 years ago
Read 2 more answers
What is the main difference between electron configuration and orbital notation?
8_murik_8 [283]

Answer:

Orbital Notation is more specific on where exactly the electron is placed.

Explanation:

When writing an electron configuration for an atom, rather than writing out the occupation of each and every orbital specifically, you instead lump all the core electrons together and designate it with a symbol of the corresponding noble gas on the Periodic Table.

the arrangement of electrons in the orbitals of an atom or molecule

While Orbital Notation is a visual transformation of the electron configuration. It shows you where each specific electron is placed and what its "spin" is.

Glad I could help!

6 0
3 years ago
The only way to separate a compound into its elements is by what?
algol [13]
Electrolysis and heat can separate a compound into its elements. 

I hope this helped you!
7 0
3 years ago
Estructura molecular del óxido nitroso​
lozanna [386]

Answer:

yes

Explanation:

3 0
3 years ago
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