We have this
<span>C M = n / V => n = C M . V = 0,25 . 0,4 = 0,1 mole </span>
<span>m Na2CO3 = n . M = 0,1 . 106 = 10,6 g</span>
Charles law gives the relationship between volume of gas and temperature.
It states that for a fixed amount of gas at constant pressure, volume of gas is directly proportional to the temperature.

where V - volume and T - temperature and k - constant

where parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
T1 - temperature in Kelvin , -206.6 °C + 273.15 = 66.55 K
T2 - 175.9 °C + 273.15 = 449.05 K
substituting the values in the equation

V = 782 mL
the new volume is 782 mL
Answer:
Calcium is heavier a little bit
Answer: A
Explanation: the only way to turn it from blue to yellow is to mix it with an acidic solution.
The moon phases maybe? Can I see the passage possibly?