The first one is exothermic because energy is a reactant, the second formula is endothermic
Answer:
Subtract the charge from the atomic number. When an ion has a positive charge, the atom has lost electrons. To calculate the remaining number of electrons, you subtract the amount of extra charge from the atomic number. In the case of a positive ion, there are more protons than electrons.
Explanation:
Answer:
Coefficients
Explanation:
Chemical equations are first written as a skeleton equation, which includes how many atoms each element and compound has. Skeleton equations are not 'balanced' because the number of atoms of each element on the left side (reactants) is not equal to the right side (products).
To balance a chemical equation, you can write coefficients in front of single elements and compounds. The coefficient multiplies with each single element and with each element in the compound.
For example, in this skeleton equation:
H₂ + Cl₂ => HCl
Reactants: Products:
2 hydrogen 1 hydrogen
2 chlorine 1 chlorine
Write the coefficient 2 in the products.
H₂ + Cl₂ => 2HCl
Now both reactant and product sides have 2 chlorine and 2 hydrogen, so the equation is balanced.
Q: A
according to this formula, we can get the mole fraction of water (n):
P(solu) = n Pv(water)
when we have Pv(solu) = 22.8 and Pv(water) = 23.8 so by substitution:
22.8 = n * 23.8
n= 0.958
- we need to get the moles of glucose:
moles of water = 500 g(mass weight) / 18 (molar weight)= 27.7 mol
n = moles of water / ( moles of water + moles of glucose)
0.958 = 27.7 / ( 27.7+ moles of glucose)
0.958 moles of glucose + 26.5 = 27.7
0.968 moles of glucose = 1.2
moles of glucose = 1.253 mol
∴ the mass of glucose = no.of glucose moles x molar mass
= 1.253 x 180 = 225.5 g
Q: B
here we also need to get n (mole fraction of water )by using this formula:
Pv(solu) = n Pv(water)
when we have Pv(solu)=132 & Pv(water)=150 so, by substition:
132= n * 150
n = 0.88
so, mole fraction of solution = 1 - 0.88 = 0.12
and we can get after that the moles of water = (mass weight / molar mass)
- no.moles of water = 85 g / 18 g/mol = 4.7 moles
- total moles in solution = moles of water / moles fraction of water
= 4.7 / 0.88 = 5.34 moles
∴ moles of the solution = total moles in solu - moles of water
= 5.34 - 4.7 = 0.64 moles solute
∴ the molar mass of the solute = mass weight of solute / no.of moles of solute
= 53.8 / 0.64 = 84 g/mole
Q: C
moles of urea (NH2)2 CO = mass weight / molar mass
= 4.49 g / 60 g /mol
= 0.07 mol
moles of methanol = mass weight / molar mass
= 39.9 g / 32 g/mol = 1.25 mol
moles fraction of methanol = moles of methanol / (moles of methanol + moles of urea )
moles fraction of methanol = 1.25 / ( 1.25+0.07) = 0.95
by substitution in Pv formula we will be able to get the vapour pressure of the solu :
Pv(solu) = n P°v
Pv(solu) = 0.95 * 89 mm Hg
∴Pv(solu) = 84.55 mmHg
Cruising at 35,000 feet in an airliner, straight toward the east,
at 500 miles per hour.
Since your speed is not changing and you're moving in a straight line,
your acceleration is zero.