Answer:
a chemical change is usually an irreversible chemical reaction. an example of this is rusting.
a physical change is usually visible while a chemical change isn't. also, a chemical change is irreversible while a physical change is.
Explanation:
Answer:
2621.75 j heat is required to increase the temperature 25.5°C to 46°C.
Explanation:
Given data:
Mass of sample = 142.1 g
Initial temperature = 25.5°C
Final temperature = 46°C
Specific heat capacity of Al = 0.90 J/g.°C
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 46°C - 25.5°C
ΔT = 20.5°C
Q = 142.1 × 0.90 J/g.°C × 20.5°C
Q = 2621.75 j
Thus, 2621.75 j heat is required to increase the temperature 25.5°C to 46°C.
Answer:
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Answer:
2 significant figures.
Explanation:
Significant Figures Rules:
1. Anything that isn't a zero is a sig fig
2. If a decimal point comes after the ones digit, everything before the decimal is counted as sig fig (i.e 2000. would be 4 sig figs).
3. If we are dealing with small decimals, the zero before and after the decimal (i.e 0.002) is a placeholder and is not counted as sig figs.
4. Any zeros between 2 significant digits is considered in sig figs (i.e 2002 would be 4 sig figs)
Since we are dealing with 87000, we see that we have no decimal point. That means our only sig figs are 8 and 7, which equals 2 sig figs.