Answer:
potassium
The third alkali metal is K (potassium). The atomic number of K (potassium) is 19. Thus, the atomic number of third alkali metal is 19
Explanation:
Answer:
If you change the number of neutrons somehow, nothing will happen because it carry's no charge at all.
Explanation:
Answer: 502 Joules
Explanation:
To calculate the mass of water, we use the equation:

Density of water = 1 g/mL
Volume of water = 40.0 mL
Putting values in above equation, we get:

When metal is dipped in water, the amount of heat released by lead will be equal to the amount of heat absorbed by water.

The equation used to calculate heat released or absorbed follows:

q = heat absorbed by water
= mass of water = 40.0 g
= final temperature of water = 20.0°C
= initial temperature of water = 17.0°C
= specific heat of water= 4.186 J/g°C
Putting values in equation 1, we get:
![q=40.0\times 4.186\times (20.0-17.0)]](https://tex.z-dn.net/?f=q%3D40.0%5Ctimes%204.186%5Ctimes%20%2820.0-17.0%29%5D)

Hence, the joules of heat were re-leased by the lead is 502
Answer:

Explanation:
We are asked to find how many moles of sodium carbonate are in 57.3 grams of the substance.
Carbonate is CO₃ and has an oxidation number of -2. Sodium is Na and has an oxidation number of +1. There must be 2 moles of sodium so the charge of the sodium balances the charge of the carbonate. The formula is Na₂CO₃.
We will convert grams to moles using the molar mass or the mass of 1 mole of a substance. They are found on the Periodic Table as the atomic masses, but the units are grams per mole instead of atomic mass units. Look up the molar masses of the individual elements.
- Na: 22.9897693 g/mol
- C: 12.011 g/mol
- O: 15.999 g/mol
Remember the formula contains subscripts. There are multiple moles of some elements in 1 mole of the compound. We multiply the element's molar mass by the subscript after it, then add everything together.
- Na₂ = 22.9897693 * 2= 45.9795386 g/mol
- O₃ = 15.999 * 3= 47.997 g/mol
- Na₂CO₃= 45.9795386 + 12.011 + 47.997 =105.9875386 g/mol
We will convert using dimensional analysis. Set up a ratio using the molar mass.

We are converting 57.3 grams to moles, so we multiply by this value.

Flip the ratio so the units of grams of sodium carbonate cancel.




The original measurement of moles has 3 significant figures, so our answer must have the same. For the number we found that is the thousandth place. The 6 in the ten-thousandth place to the right tells us to round the 0 up to a 1.

There are approximately <u>0.541 moles of sodium carbonate</u> in 57.3 grams.
Answer:
The answer to your question is It will be formed 0.39 moles of H₂
Explanation:
Data
moles of H₂ = ?
moles of HCl = 0.78
moles of Zinc = excess
Balanced chemical reaction
2 HCl + Zn ⇒ 1 H₂ + ZnCl₂
Process
1.- Use proportions to solve this problem. Consider the coefficients of the balanced reaction.
2 moles of HCl ---------------------- 1 mol of H₂
0.78 moles of HCl ----------------- x
x = (0.78 x 1) / 2
- Simplification
x = 0.78 / 2
- Result
x = 0.39 moles of H₂