Answer:
Gneiss forms by regional metamorphism from both high temperature and pressure. Quartzite and marble are the most commonly used metamorphic rocks.
Answer:
No
Explanation:
Filling a beaker 200ml of water is not bad because Each beaker's capacity may vary according to the size of different beaker.
A. because a chemical change is something that's changing
0.448 moles of ions will form when a 42.66-gram sample of magnesium chloride is dissolved in water (option A).
<h3>How to calculate number of moles?</h3>
According to this question, when magnesium chloride (MgCl2) dissolves in water, it dissociates into magnesium ions and chloride ions as follows:
MgCl2(aq) ⟶ Mg2+(aq) + Cl−(aq)
However, if a 42.66-gram sample of magnesium chloride is dissolved in water, this means that 42.66g/molecular mass of MgCl2 will be the number of moles of the ionic products.
molecular mass of MgCl2 = 95.3g/mol
moles = 42.66g ÷ 95.3g/mol = 0.448mol
Therefore, 0.448 moles of ions will form when a 42.66-gram sample of magnesium chloride is dissolved in water.
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Answer:
Final temperature = 83.1 °C
Explanation:
Given data:
Mass of concrete = 25 g
Specific heat capacity = 0.210 cal/g. °C
Initial temperature = 25°C
Calories gain = 305 cal
Final temperature = ?
Solution:
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 = T2 - T1
305 cal = 25 g ×0.210 cal/g.°C × T2 - 25°C
305 cal = 5.25cal/°C × T2 - 25°C
305 cal / 5.25cal/°C = T2 - 25°C
58.1 °C = T2 - 25°C
T2 = 58.1 °C + 25°C
T2 = 83.1 °C
