Answer: The millimoles of sodium carbonate the chemist has added to the flask are 256
Explanation:
Molarity is defined as the number of moles dissolved per liter of the solution.
To calculate the number of moles for given molarity, we use the equation:
.....(1)
Molarity of
solution = 1.42 M
Volume of solution = 180.0 mL
Putting values in equation 1, we get:

Thus the millimoles of sodium carbonate the chemist has added to the flask are 256.
Answer = c
Conservation of mass (mass is never lost or gained in chemical reactions), during chemical reaction no particles are created or destroyed, the atoms are rearranged from the reactants to the products.
Density is equal to the ratio of mass to the volume.
The mathematical expression is given as:

Density of silver metal bar=
Convert
into g/L
= 0.001 L
Thus, density = 
= 
Volume = 0.5 L
Put the values,


=
Now, convert gram into kg
1 g = 0.001 kg
Therefore, mass in kg= 
= 5.25 kg
Thus, mass of silver metal bar in kg=5.25 kg
Answer:
Heat transferred, Q = 1542.42 J
Explanation:
Given that,
Mass of water, m = 30 grams
Initial temperature, 
Final temperature, 
We need to find the energy transferred. The energy transferred is given by :

c is specific heat of water, c = 4.18 J/g °C
So,

So, 1542.42 J of energy is transferred.