Answer:
B. It undergoes a physical change.
Explanation:
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In this case, since we know that chemical changes lead to the formation of new atoms and/or compounds due to the bonds rearrangement of the initial substances and the physical changes occur without changing the composition of the initial substances, we can infer that, since melting is a process that changes the phase of matter from solid to liquid without changing the identity of the initial substance, the answer to this question would be B. It undergoes a physical change. because the other options describe chemical changes.
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Gabriel Fahrenheit invented the thermometer
The question here is solved using basic chemistry. CaCl2(aq) is an ionic compound which will have the releasing of 2 Cl⁻ ions ions in water for every molecule of CaCl2 that dissolves.
CaCl2(s) --> Ca+(aq) + 2 Cl⁻(aq)
[Cl⁻] = 0.65 mol CaCl2/1L × 2 mol Cl⁻ / 1 mol CaCl2 = 1.3 M
The answer to this question is [Cl⁻] = 1.3 M
Answer:
The method is accurate in the calculation of the 
Explanation:
As a first step we have to calculate the <u>average concentration </u>of find it by the method.
Then we have to find the<u> standard deviation:</u>
For the confidence interval we have to use the formula:
μ=Average±
Where:
t=t student constant with 95 % of confidence and 5 data=2.78
μ= 
± 
upper limit: 0.84
lower limit: 0.75
If we compare the limits of the value obtanied by the method (Figure 1 Red line) with the reference material (Figure 1 blue line) we can see that the values obtained by the method are within the values suggested by the reference material. So, it's method is accurate.
Answer:
4 significant digits
Explanation:
Zeroes placed between other digits are always significant
