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Natasha2012 [34]
3 years ago
8

List four observations that indicate that a chemical reaction may be taking place

Chemistry
1 answer:
olga55 [171]3 years ago
6 0

Answer :

For a given reaction to take place, there might be at least one of these (7) signs;

- formation of gas bubbles, formation of a precipitate (creation of a solid from a solution), a change in color, a change in volume (due to change in density), a change in temperature (endothermic or exothermic), change in taste or smell and emission of light or fire..


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Sodium and chlorine react to form sodium chloride. If there are 1.4 moles of sodium used, how many moles of chlorine were requir
sammy [17]

Answer:

0.7 moles of Chlorine gas is required.

Explanation:

The reaction is balanced as follows:

2Na + Cl_{2} ------>  2NaCl

According to stoichiometry,

2 mole Sodium reacts with 1 mole Chlorine gas

∴1 mole Sodium reacts with 1/2 moles of Chlorine gas

∴1.4 mole sodium reacts with 1.4/2 moles of Chlorine gas

                                                = 0.7 moles of Chlorine gas

So, 0.7 moles of Chlorine gas is required.

3 0
3 years ago
A chemistry student needs 60.0 ml of ethanolamine for an experiment. By consulting the CRC Handbook of Chemistry and Physics, th
BARSIC [14]

Answer:

The student should weigh out 61.2g of ethanolamine [6.12 * 10]

Explanation:

In this question, we are expected to calculate the mass of ethanolamine needed to make 60.0ml of it given that the density of the ethanolamine in question is 1.02g/cm^3

Mathematically, it has been shown that mass = density * volume

Hence, by multiplying the density by the volume, we get the mass.

Now, from the question we can see that we have the values for the density and the volume. We now need to get the mass.

Since cm^3 is same as ml, we need not perform any conversion.

Hence, the needed mass is:

60 * 1.02 = 61.2g

6 0
4 years ago
As you move from left to right across the periodic table, each element has one more ________ than the element before it. questio
mylen [45]
The answer should be 2) electrons. 

The elements in the periodic table are arranged by increasing atomic number, which is also the number of protons in an element. For example, Carbon has 6 protons, it is the sixth element on the table. While Nitrogen, which has 7 protons, is after Carbon. 

In atoms, the number of protons equals to the number of electrons too, if the number of electrons does not equal to the number of protons, the substance is no longer atom, but ion. So, the answer to this is 2) electrons, as the elements on the table is arranged according to increasing atomic numbers. 
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Which ones are chemical change help please its a timed test!
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I think “A” is the right answer
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Which element is presented in all organic compounds
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Carbon and hydrogen
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4 years ago
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