1) Answer: A hot pack feels warm when chemicals in it combine.
Explanation: Reactions or process in which heat is released(produced) are known as exothermic reactions or process and those in which the heat is absorbed are known as endothermic reactions or process.
If a beaker feels cools when chemical in it react then it means the chemicals have absorbed the heat energy from its surroundings and so it is an example of an endothermic process.
A hot pack feels warm when chemicals in it combine means the energy is released in the chemical reaction and so it is an example of an exothermic process.
Plants use the sun's energy for photosynthesis which is a process of forming food for the plants. Energy acts as a reactant in this process and so it is an example of endothermic process.
Frying an egg by heating it on a stove is an example of an endothermic process as the heat is required to fry the egg.
So, the only exothermic process is the second one, "A hot pack feels warm when chemicals in it combine."
2) In the given equation, heat is written as a product means the heat is released in the equation and so it is an example of an exothermic reaction.
So, the correct choice is the last one " It is exothermic because energy is released."
Answer:
Convert the mass of each element to moles using the molar mass from the periodic table. then Divide each mole value by the smallest number of moles calculated. Round to the nearest whole number
Answer:
Ammonium bromide can be prepared by the direct action of hydrogen bromide on ammonia. It can also be prepared by the reaction of ammonia with iron(II) bromide or iron(III) bromide, which may be obtained by passing aqueous bromine solution over iron filings.
Explanation:
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Mass is the property of a physical body and the resistance to acceleration when a net force is applied on the body.
The atomic mass of sodium (Na) is = 22.98
The atomic mass of nitrate (N) is = 14.00
The atomic mass of oxygen (O) is = 15.99
The sodium nitrate (NaNO3) consists of the atomic masses of Na+N+(O)3 = 85 grams
Therefore, the mass of 6.5 mol of sodium nitrate is = 6.5 * 1 mol of NaNO3
= 6.5 * (85)
= 552.50 grams
Answer:
102g of crystals
Explanation:
When the Cr(NO₃)₃⋅9H₂O is dissolved in water at 15°C, the maximum mass that water will dissolve in the equilibrium is 208 g per 100g of water. When you heat the water, this mass will increases.
In this problem, at 35°C the water dissolves 310g in 100g of water, as in the equilibrium at 15°C the maximum mass is 208g, the mass of crystals that will form is:
310g - 208g = <em>102g of crystals</em>
<em>-Crystals are the Cr(NO₃)₃⋅9H₂O that is not dissolved-.</em>
I hope it helps!
