Answer:
Melting of ice is a physical change and during this change latent heat of fusion, that is, heat required to convert 1 g of a solid substance into liquid state will keep the temperature constant unless and until all the solid changes into liquid. On the other hand, a change in which a new product is formed due to change in chemical composition of the reacting species is known as a chemical change. During a chemical change, there will occur change in temperature. So, when a substance is set on fire then there will occur change in temperature of the substance. Hence, it means it is a chemical change.
Explanation:
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Answer:
Explanation:
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In this case, considering the Avogadro's number, which relates the number of particles and one mole, we can infer that 1 mole of any element contains 6.022x10²³ atoms as shown below:
Thus, we compute the number of atoms in 0.035 moles as shown below:
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NaOH + HBr =⇒ NaBr + H2O
35.0 ml HBr x 1 liter/1000 mL x 0.140 moles HBr/ liter = 0.0049 moles HBr
0.0049 moles HBr x 1mole NaOH/1mole HBr = 0.0049 moles HBr
0.0049 moles HBr x 1 liter NaOH/0.200 moles NaOH x 1000 mL/1liter= 24.5 mL NaOH
<span>This problem uses the
relationship between Ka and the concentrations of the ions. Calculations are as follows:</span>
<span>
</span><span>1.9 x 10-5</span>= x^2 / (0.25 - x)
<span>x is very small and the denominator is approximately equal to 0.25. Thus, x is 2.2 x 10^-3
</span><span>pH = -log (2.2 x 10^-3)</span> = 2.66
