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Answer:
Explanation:
Hello!
In this case, since the freezing point depression caused by the addition of a solute, we use the following formula:
Thus, we first need to compute the molality of each solute, as shown below:
Next, since NaCl has two ionic species, one Na⁺ and one Cl⁻, and CaCl₂ three, one Ca²⁺ and two Cl⁻, the van't Hoff's factors are 2 and 3 respectively, therefore the freezing point depressions turn out:
It means that CaCl₂ is still better than NaCl because produces involves a higher melting point for the ice, so it would melt faster.
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<u>Given</u> :
- Amount = 20 kg
- Heat energy absorbed = 237,000 J
- Temperature change = 15 °C
<u>Formula applied</u> :
- Q = absorbed heat
- m = mass
- c = specific heat capacity
- ΔT = temperature change
Let's solve for c !
⇒ 237,000 = 20 × c × 15
⇒ c = 237,000 ÷ 300
⇒
∴ The specific heat capacity of granite is <u>790 J kg⁻¹ K⁻¹</u>.
This problem is honestly, very easy. Just grab a periodic table and find the element in Group 1 and Period 7. But first, let's discuss how the elements are arranged systematically in a periodic table. There are a lot of scientists who contributed to it, but the most famous one is Dimitri Mendeleev. He arranged the elements according to their atomic number. The elements starts from 1 which is Hydrogen up to the heaviest known elements which is Oganesson with an atomic number of 118. As you can observe, there is a gap between groups 3 and 4. This is done so that the periodic table does not take too much space horizontally. Thus, they are just placed at the bottom. These elements are called lanthanides (upper row) and actinides (lower row). The rows in the periodic table are called groups, and the columns are called periods.
Now, the element at the lower left corner (Group 1, Period 7) is Francium, abbreviated as Fr. It has an atomic number of 87. Some elements are actually synthesized, but Francium is a naturally occurring radioactive element. It was discovered by Marguerite Perey in France.
Now, the element at the lower left corner (Group 1, Period 7) is Francium, abbreviated as Fr. It has an atomic number of 87. Some elements are actually synthesized, but Francium is a naturally occurring radioactive element. It was discovered by Marguerite Perey in France.