C. NaCl
sodium chloride is made up of metals and non metals
If you'd like the full working, here it is:
I calculated this by using the formula triangle.
Mass
Number Formula
Of moles Mass
To calculate the number if moles in a substance, you need to divide the Mass by the Formula mass. You get the formula mass by adding the atomic masses of the elements in the compound together. In this situation, H2O, it would be two hydrogen molecules plus one oxygen molecule which is 2 + 16. This is because the atomic mass of Hydrogen is 1 and the atomic mass of Oxygen is 16.
Now that we have the Formula mass we can go ahead and do the calculation since we already have the Mass. You do as follows:
Mass divided by Formula mass which is in this case - 25 divided by 18
By doing this calculation you will get the answer which is 1.38 moles which can be rounded to 1.4
Hope this helps :)
Answer:
Explanation:
We are asked to find how much heat a sample of water absorbed. Since we are given the mass, temperature, and specific heat, we will use the following formula.
The mass (m) of the sample is 112.5 grams. The specific heat capacity of water (c) is 4.184 Joules per gram degree Celsius. The difference in temperature (ΔT) is found by subtracting the initial temperature from the final temperature.
- ΔT= final temperature - initial temperature
The water was heated from 12.5 degrees Celsius to 92.1 degrees Celsius.
- ΔT= 92.1 °C - 12.5 °C= 79.6°C
Now we know three variables and can substitute them into the formula,
- m= 112.5 g
- c= 4.184 J/g °C
- ΔT= 79.6 °C
Multiply the first 2 numbers. Note the units of grams cancel.
Multiply again. This time the units of degrees Celsius cancel.
37, 467.72 Joules of heat are absorbed by the sample fo water.
Answer: C₃H₂
Explanation:
1) Since you are told naphthelene is a hydrocarbon, you know that its chemical formula only has atoms of C and H.
2) Since combustion adds O but not C nor H, you know that all the C and H present in the products come from the naphthelene sample.
3) Calculate the amount of C in 13.20 grams of CO₂:
Use atomic masses:
C: 12.01 g/mol
O: 16.00 g/mol
⇒ molar mass of CO₂ = 12.01 g/mol + 2×16.01 g/mol = 44.01 g/mol
Proportion of C in 13.20 g of CO₂
12.01 g C / 44.01 g CO₂ = x / 13.20 g CO₂ ⇒
x = 13.20 g CO₂ × 12.01 g C / 44.01 g CO₂ = 3.602 g C
3) Calculate the mass of H in 1.80 g of H₂O
Atomic masses:
H: 1.01 g/mol
O: 16.0 g/mol
Molar mass H₂O = 18.02 g/mol
Proportion of H in 1.80 g H₂O
2.02 g H / 18.02 g H₂O = x / 1.80 g H₂O
x = 1.80 gH₂O × 2.02 g H / 18.02 gH₂O = 0.202 g H.
4) Calculate the number of moles of C and H in the masses calculated above
Number of moles of C = 3.602 g C / 12.01 g/mol = 0.3 mol
Number of moles of H = 0.202 g / 1.01 g/mol = 0.2 mol
5) Divide both amounts by the smallest one to calculate the proportion in moles:
C: 0.3 / 0.2 = 1.5 mol
H = 0.2 / 0.2 = 1 mol
Multiply by 2 to obtain integers:
C: 3
H: 2
6) Then the proportion leads to the empirical formula C₃H₂
ANSWER:
in words equations we use words to show what happens using words a chemical reaction.
