Answer:
C. a change in the total mass of the product
Explanation:
A chemical reaction is a reaction that alters the chemical composition of the substances involved. Based on the options in this question, a chemical reaction possess the following features:
- The atoms of the substance called reactants are rearranged into products but the total number of atoms remain the same after the reaction.
- A change in odor occurs as one of the indicators that a chemical reaction has taken place.
- Energy is either absorbed (endothermic) or released (exothermic) in the chemical reaction.
However, one untrue option is that "there is a change in the total mass of the product". The total mass of a chemical reaction does not change i.e. remains the same, before or after the reaction in accordance to the law of conservation of mass.
Answer:
<h3> GLACIERS AND ICE CAPS </h3>
Explanation:
According to the U.S. Geological Survey, most of that three percent is inaccessible. Over 68 percent of the fresh water on Earth is found in icecaps and glaciers, and just over 30 percent is found in ground water. Only about 0.3 percent of our fresh water is found in the surface water of lakes, rivers, and swamps.
Answer:
We will not know immediately
Explanation:
The distance of star Betelgeuse = 325 light years
Therefore, if it where to explode, at the location, we would have a supernovae such that the luminosity of the star multiplies several multiple times
However, due to the distance of Betelgeuse from the Earth, it will take the light of the explosion, 325 years to reach Earth and the explosion as it happens will not be noticed here on Earth immediately
The chemical equation is missbalaced.
The right balanced chemical equation is:
<span>2NaHCO3(s) + 129 kJ ---> Na2CO3(s) + H2O(g) + CO2(g)
Then, now you know that 2 moles of NaHCO3 requires 129 kJ heat, and you just need to convert 25.5 grams of NaHCO3 into number of moles to calculare the amount of heat needed.
A) Number of moles in 25.5 g of NaHCO3, n:
n = grams / molar mass
molar mass NaHCO3 = 23 g/mol + 1g/mol + 12g/mol + 3*16g/mol = 84 g/mol
n = 25.5 g / 84 g/mol = 0.304 mol
B) Heat required
Make the proportion with the theoretical ratio:
2mol / 129 kJ = 0.304 mol / x
=> x = 0.304 mol * 129 kJ / 2 mol = 19.608 kJ
Answer: 19.6 kJ
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I think it would be C.100.5cm or D.100.5ml hope that helps
