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Gnesinka [82]
3 years ago
13

How do you tell if a reaction is endothermic or exothermic using only the written formula

Chemistry
1 answer:
irina [24]3 years ago
6 0
You know if it's endothermic or exothermic by doing the enthalpy reaction. If the change of temperature is negative then it is exothermic, while positive is endothermic. If you get -22K then its exothermic, but if you get +22 its endothermic.
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Is sodium a solid, liquid, or gas
Sedaia [141]

Sodium is a solid and a liquid

Hope this helps

6 0
3 years ago
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This is my almost last question plsss help
Morgarella [4.7K]
The third one is correct, not sure abt another one
7 0
2 years ago
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Calculate the mean of 2, 5 and 3. write your answer to 2 decimal places. please help me on this
makvit [3.9K]

Hello.

The answer is: 3.3333

To get the answer add 2,5 and 3 that is 10 then divide by 3 to get 3.3

Have a nice day

6 0
3 years ago
Calculate the number of atoms of sodium in a 4.5-gram sample
allochka39001 [22]

Answer:

1.18×10²³ atoms.

Explanation:

From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms.

From the above concept, 1 mole of sodium also contains 6.02×10²³ atoms.

1 mole of sodium = 23 g.

Thus,

23 g of sodium contains 6.02×10²³ atoms.

Therefore, 4.5 g of sodium will contain = (4.5 × 6.02×10²³)/23 = 1.18×10²³ atoms.

From the above calculation,

4.5 g of sodium contains 1.18×10²³ atoms.

7 0
3 years ago
Barium nitrate has the formula Ba( NO3)2. Which statement is true about barium nitrate?
OLga [1]
I found these four statements for that question:

Each molecule contains four different elements.

Each molecule contains three atoms.

Each molecule contains seven different bonds.

Each molecule contains six oxygen atoms.

The last one is true. Each molecule contains six oxygen atoms.
The number to the right of O and of (NO3) ares subscripts.


The chemical formula uses subscripts to indicate the number of atoms.



The subscript 2 in (NO3)2 means that there are two NO3 radicals.


And the subscript 3 to the right of O means that each NO3 radical has three atoms of O.

Then, the number of atoms of O is 2 * 3 = 6.


So, the true statement is the last one: each molecule of Ba (NO3)2 has six atoms of O.


From that molecule you can also tell:

- Each molecule contains one atom of barium

- Each molecule contains two atoms of nitrogen

- Each molecule contains two NO3 radicals

4 0
3 years ago
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