Answer:
The answer to your question is 32.44 moles
Explanation:
Data
moles of Na₂CO₃ = ?
volume = 9.54 l
concentration = 3.4 M
Formula
Molarity = 
Solve for number of moles
number of moles = Molarity x volume
Substitution
Number of moles = (3.4)( 9.54)
Simplification
Number of moles = 32.44
Weight of the balloon = 2.0 g
Six weights each of mass 30.0 g is added to the balloon.
Total mass of the balloon = 2.0 g + 6*30.0 g = 182 g
Density of salt water = 1.02 g/mL
Calculating the volume from mass and density:

Converting the volume from mL to cubic cm:

Assuming the balloon to be a sphere,
Volume of the sphere =
π

r = 3.49 cm
Radius of the balloon = 3.49 cm
Diameter of the balloon = 2 r = 2*3.49 cm = 6.98cm
Answer:
19.6 J
Step-by-step explanation:
Before the ball is dropped, it has a <em>potential energy
</em>
PE = mgh
PE = 0.2 × 10 × 9.8
PE = 19.6 J
Just before the ball hits the ground, the potential energy has been converted into kinetic (<em>mechanical</em>) energy.
KE = 19.6 J
Carbon and silicon have same number of valance electrons which is 4 electrons
Now, Barium is a 2nd group element. So, it has two valance electrons.
Silicon is a 16th group element and it has 4 valance electrons as does the carbon. This is because they both stay in the same group in the periodic table.
Neon is a noble gas which has 8 valance electrons and stays in the 18th group.
Therefore, carbon and silicon have same number of valance electrons which is 4 electrons.
<h3>What are Valence electrons ?</h3>
The electrons in an atom's outermost shell, or energy level, are called valence electrons. For instance, the valence electrons of oxygen are six, with two in the 2s subshell and four in the 2p subshell.
- The number of valence electrons for neutral atoms is the same as the number of the atom's main group. A periodic table element's column can be used to determine its main group number. For instance, carbon, which belongs to group 4, has four valence electrons. Group 6 oxygen contains six valence electrons.
Learn more about Valence electrons here:
brainly.com/question/371590
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We can solve this problem when we use the conditions of a gas at standard temperature and pressure. It has been established that at STP where the temperature is 0 degrees Celsius and the pressure is 101.325 kPa, the volume of 1 mole of gas is 22.4 L. We will use this data for the calculations.
68.5 L ( 1 mol O2 / 22.4 L O2 ) = 3.06 mol O2