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vovikov84 [41]
3 years ago
7

Commercially available hot packs are simple in design: a pouch with water on one side, isolated by a barrier from a specific sal

t on the other side. When the barrier is broken, the salt and water mix and the solution becomes hot. Select the statement that is true about the reaction occurring in hot packs.A. The hot pack absorbs heat from the environment.
B. The reaction between the salt and water is exothermic.
C. The reaction between the salt and water is endothermic.
D. The reaction between the salt and water is neither endothermic nor exothermic.
Chemistry
1 answer:
liq [111]3 years ago
3 0

Answer:

b :)

Explanation:

an exothermic reaction is when heat/light is produced. heart is produced from this reaction so it is exothermic

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Arrange the forms of electromagnetic radiation in order of decreasing energy (from highest energy to lowest energy). You are cur
solmaris [256]

Answer:

gamma rays > X-rays > ultraviolet radiation > visible light > infrared > radio waves.

Explanation:

Electromagnetic waves are those waves that require no material medium for propagation. They can travel through space and they all move at the speed of light.

Electromagnetic waves are composed of both electric and magnetic fields which are mutually at right angles to each other.

The order of decreasing energy of electromagnetic waves is;

gamma rays > X-rays > ultraviolet radiation > visible light > infrared > radio waves.

3 0
3 years ago
How many moles of sodium ions are present in 0.25 kg of a 2.0 m solution of sodium chloride in water
LenKa [72]

0.50 is the answer on edge

8 0
4 years ago
What is the pH of a mixture of 0.042 M NaH2PO4 and 0.058 M Na2HPO4? Hint: The pKa of phosphate is 6.86.
AlekseyPX

Answer:

The pH value of the mixture will be 7.00

Explanation:

Mono and disodium hydrogen phosphate mixture act as a buffer to maintain pH value around 7. Henderson–Hasselbalch equation is used to determine the pH value of a buffer mixture, which is mathematically expressed as,

pH=pK_{a} + log(\frac{[Base]}{[Acid]})

According to the given conditions, the equation will become as follow

pH=pK_{a} + log(\frac{[Na_{2}HPO_{4} ]}{[NaH_{2}PO_{4}]})

The base and acid are assigned by observing the pKa values of both the compounds; smaller value means more acidic. NaH₂PO₄ has a pKa value of 6.86, while Na₂HPO₄ has a pKa value of 12.32 (not given, but it's a constant). Another more easy way is to the count the acidic hydrogen in the molecular formula; the compound with more acidic hydrogens will be assigned acidic and vice versa.

Placing all the given data we obtain,

pH=6.86 + log(\frac{0.058}{0.042})

pH=7.00

5 0
3 years ago
The basic principle in balancing a chemical equation is to ______. hints
Natalija [7]
Answer:  obey the "law of conservation of mass".
_____________________________________
5 0
3 years ago
Read 2 more answers
1.Salts consist of atomic particles that have an (blank) charge.
enyata [817]
The nonmetal elements have a negative charge.
5 0
4 years ago
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