Answer:
For neutral atoms, the number of valence electrons is equal to the atom's main group number. The main group number for an element can be found from its column on the periodic table. For example, carbon is in group 4 and has 4 valence electrons. Oxygen is in group 6 and has 6 valence electrons.
Explanation:
hope this help
There are no states in the picture, but Na should have a "(s)" after it, and Cl2 should have a "(g)" after it. NaCl should have an "(s)". Chlorine is a diatomic element so it has a "2" subscript on it.
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Answer: Heat of the solution = mass water × specific heat water × change in temperature
mass water = 260ml (1.00g/ml ) = 260g
specific heat of water = c(water) = 4.184J/ g°C
Heat change of water = final temperature - initial temperature
= 26.5 - 21.2
= 5.3 °C
H = 260 g ( 4.184J/g°C ) (5.3°C) = 5765J
Molar heat = 
= 16473J/mol
Explanation: finding molar heat requires first to look at specific heat of water and the change of water temperature
Answer:

Explanation:
The density formula is mass over volume.

Rearrange the formula for the mass, m. Multiply both sides of the formula by v.


Mass can be found by multiplying the density and volume. The density is 0.65 grams per milliliter and the volume is 45.0 cubic centimeters.
- A cubic centimeter is equal to a milliliter.
- Therefore, 45 cubic centimeters also equals 45 milliliters.

Substitute the values into the formula.

Multiply. Note the milliliters, or mL will cancel out.


The mass of the wood is 29.25 grams.