Answer:
109.0
Explanation:
When adding or subtracting values, you must round your answer to the same "place" as the measurement with its last significant figure <em>furthest to the left</em>.
That is, you round off to the same number of decimal places as the measurement with the <em>fewest decimal places</em>.
43.<u>0
</u>
50.<u>0</u>
<u>+16.0
</u>
109.<u>0</u>
In each measurement, the “0” is the significant figure furthest to the left, so you round off the number to the “tenths" place. That's the last column that the measurements share.
109.0 → 109.0 (rounded to the “tenths” place)
In other words, you do not round off, and the sum has four significant figures.
<span>Supporting combustion is a chemical property because it involves a chemical reaction that can only be reversed with another chemical reaction.</span>
Explanation:
They put five crickets in each of three identical containers. They s ... to 15°C, one to 20°C, and one to 25°C. Then they count the number of cricket chirps in each container
Answer: 0.34 mol
Justification:
1) Hepta means 7, so heptahyrate means 7 parts of water. On mole of magnesium sulfate heptadydrate has seven moles of water.
2) The formula of magnesium sulfate heptahydrate is:
Mg SO4 . 7 H2O
3) Calcualte the number of moles of the compound by dividing the mass in grams by the molar mass of formula.
molar mass:
Mg: 24.3 g/mol
S: 32.1 g/mol
O4: 4 * 16.0 g/mol = 64.0 g/mol
H2: 2 * 1.0 g/mol = 2.0 g/mol
O: 16 g/mol
Molar mass = 24.3 g/mol + 32.1 g/mol + 64.0 g/mol + 2.0 g/mol + 16.0 g/mol = 138.4 g/mol
number of moles = mass in grams / molar mass = 6.81 g / 138.4 g/mol = 0.049 mol
4) As stated, there are 7 moles of H2O per each mol of heptahydrate compoind, so the number of moles of water is 7 * 0.049 mol = 0.343 mol
Answer: 0.34 mol
Answer: nucleons
Explanation:
The nucleons are the particles that constitue the nuclei of the atoms. Those are protons and neutrons.
They are not elementary particles (quarks are the elementary particles that form both protons and neutrons).
Protons are the particles that define the elements. Any different elements have different number of protons. H has one proton, He has 2 protons, Li has three protons, Na has 11 protons, U has 92 protons.
Protons are positively charged and the number of protons in any neutral atom is equal to the number of electrons (the electrons, which are elementary negatively charged particles, are around the nucleous).
Neutrons have not charge and are responsible for the stability of the nuclei. They are fundamental to avoid that the repulsion forces between the positively charged protons ends causing the collapse of the nuclei.