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miskamm [114]
3 years ago
15

Sumerians were the first to invent plows, 12 month calendars and _____

Chemistry
2 answers:
drek231 [11]3 years ago
5 0
They've created many things and the created wheeled carts d
Arte-miy333 [17]3 years ago
4 0

your answer will be D) wheeled carts!

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In what two places minerals are form?
larisa [96]
In earths surface or the bottom of the Ocean
3 0
3 years ago
2) Write a hypothesis for the Observation and question below. Be sure to use the proper “If…, then…” format in your answer. Iden
Anna [14]

Answer:

If one astronaut used more force, then that one would be faster than the other. The independent variable is force. The dependent variable is speed.

Explanation:

Force is what is to be changed. Speed is what is being measured.

IV = Changed/factor DV=Measured/Changes by factor

4 0
3 years ago
How much heat in kj is released by burning 9.5 grams of methane?
tatyana61 [14]
Methane is the compound CH4, and burning it uses the reaction:

CH4 + O2 -> CO2 + H2O, which is rather exothermic. To find the heat released by burning a certain amount of the substance, you should look at the bond enthalpy of each compound, and then compare the values before and after the reaction. In methane, there are 4 C-H bonds, which have bond energy of 416 kj/mol, resulting in a total bond energy of 1664 kj/mol. O2 is 494 kj/mol. Therefore we have a total of 2080 kj/mol on the left side. On the right side we have CO2, which has 2 C=O bonds, each at 799 kj/mol each, resulting in 1598 kj/mol, and H2O has 2 O-H bonds, at 459kj/mol each, resulting in a total of 2516 kj/mol on the right hand side. Now, this may be confusing because the left hand side seems to have less heat than the right, but you just need to remember: making minus breaking, which results in a total change of 436kj/mol heat evolved.

Now it is a simple matter of find the mols of CH4 reacted, using n=m/mr.

n = 9.5/16.042 = 0.592195 mol

Therefore, if we reacted 0.592195 mol, and we produced 436 kj for one mol, the total amount of energy evolved was 436*<span>0.592195 kj, or 258.197 kj.</span>
7 0
3 years ago
how to identify amphiprotic compounds, if i give you the chemical structure or name of the compound/molecule.
Sonja [21]

Amphiprotic compounds are able to both donate and accept a proton.

Amphiprotic compounds contain a hydrogen atom and lone pair of valence electron.

For example, HSO₃⁻ (hydrogen sulfate ion) is an amphiprotic compound.

Balanced chemical equation for reaction when HSO₃⁻ donate protons to water:

HSO₃⁻(aq) + H₂O(l) ⇄ SO₄²⁻(aq) + H₃O⁺(aq).

Ka = [SO₄²⁻] · [H₃O⁺] / [HSO₃⁻]

Balanced chemical equation for reaction when HSO₃⁻ accepts protons from water:

HSO₃⁻(aq) + H₂O(l) ⇄ H₂SO₄(aq) + OH⁻(aq).

Kb = [H₂SO₄] · [OH⁻] / [HSO₃⁻]

Water (H₂O), amino acids, hydrogen carbonate ions (HCO₃⁻) are examples of amphiprotic species.

Another example, water is an amphiprotic substance:

H₂O + HCl → H₃O⁺ + Cl⁻

H₂O + NH₃ → NH₄⁺ + OH⁻

More about amphiprotic compounds: brainly.com/question/3421406

#SPJ4

7 0
1 year ago
If the pressure of the reactants increase, What happens to the product.
EastWind [94]

Increasing the pressure on a reaction involving reacting gases increases the rate of reaction. Changing the pressure on a reaction which involves only solids or liquids has no effect on the rate.

7 0
3 years ago
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