Gas i took the test plz mark brainliest!
Respiratory system and circulatory system both are responsible to control the breathing in Human body.
Answer:
The answer to your question is below
Explanation:
a)
Number of atoms = ?
moles of Fe = 4.75
-Use proportions to solve this problem
1 mol of Fe --------------------- 6.023 x 10²³ atoms
4.75 moles --------------------- x
x = (4.75 x 6.023 x 10²³) / 1
x = 2.86 x 10²⁴ / 1
Number of atoms = 2.86 x 10²⁴
b)
Number of moles = ?
moles of 1.058 moles of H₂O
I think this question is incorrect, maybe you wish to know the number of atoms or grams of H₂O.
c)
Number of atoms = ?
moles of Fe = 0.759
1 mol of Fe ------------------ 6.023 x 10²³ atoms
0.759 moles --------------- x
x = (0.759 x 6.023 x 10²³) / 1
x = 4.57 x 10²³ / 1
Number of atoms of Fe = 4.57 x 10²³ atoms
d)
Number of molecules = ?
moles of H₂O = 3.5 moles
1 mol of H₂O ------------------ 6.023 x 10²³ molecules
3.5 moles ------------------ x
x = (3.5 x 6.023 x 10²³) / 1
x = 2.11 x 10²⁴ molecules
Number of molecules = 2.11 x 10²⁴
A melting point of over 700 C and a density of less than 2 g/cm3 can be observed for many group 2 elements. In this group, the density increases on moving down the group, whereas the melting point increases upto calcium and then starts decreasing.
Calcium, symbol Ca is the element with melting point around 840 C and density of 1.55 g/cm3 which is closest to the specified data range .
