Answer:
We have 1.361 moles in the sample
Explanation:
Mass of iron = 76.02g
Molar mass of iron = 55.845 g/ mole ( This we can find in the periodic table, and menas that 1 mole of iron has a mass of 55.845 g).
To calculate the number of moles we will use following formula:
moles (n) = mass / molar mass
moles iron = 76.02g / 55.845 g/ mole
moles iron = 1.36127 moles
To use the correct number of significant digits we use the following rule for multiplication and division :
⇒ the number with the least number of significant figures decides the number of significant digits.
⇒76.02 has 4 digits ( 2 after the comma) and 55.845 has 5 digits (3 after the comma).
⇒ this means 1.361 moles
We have 1.361 moles in the sample
Answer:
the first one to the third box
the second one to the fourth box
the third one to second box
and the fourth one to the first box
Explanation:
Answer:
Well they help us understand the properties of matter of course!
Answer:
Sr is the more metallic element
Bi is the more metallic element
O is the more metallic element
As is the more metallic element
Explanation:
One thing should be clear; metallic character increases down the group but decreases across the period.
Hence, as we move across the period, elements become less metallic. As we move down the group elements become more metallic.
This is the basis upon which decisions were made about the metallic character of each of the elements listed above.
Answer:
Qm = -55.8Kj/mole
Explanation:
NaOH(aq) + HNO₃(aq) => NaNO₃(aq) + H₂O(l)
Qm = (mc∆T)water /moles acid
Given => 100ml(0.300M) NaOH(aq) + 100ml(0.300M)HNO₃(aq)
=> 0.03mole NaOH(aq) + 0.03mole HNO₃(aq)
=> 0.03mole NaNO₃(aq) + 0.03mole H₂O(l)
ΔH⁰rxn = [(200ml)(1.00cal/g∙°C)(37 – 35)°C]water / 0.03mole HNO₃
= 13,333 cal/mole x 4.184J/cal = 55,787J/mol = 55.8Kj/mole (exothermic)*
Heat of reactions comes from formation of H-Oxy bonds on formation of water of reaction and heats the 200ml of solvent water from 35⁰C to 37⁰C.
