Answer:
Infectious diseases are commonly transmitted through direct person-to-person contact.
The main four pathogens are virus, bacteria, protists and fungi.
Bacteria, fungi and protists can reproduce wherever the conditions are warm, with plenty of moisture, nutrients, and space. Viruses can only reproduce by invading living cells.
Answer:
This question appears incomplete
Explanation:
This question appears incomplete because of the absence of options. However, hydrogen is placed in group 1 because it has just one electron in it's outermost shell (which happens to be the only shell it has) just like every other group 1A/group 1 element. While helium is placed in group 8A/group 18 because it has a completely filled outermost shell (which is also the only shell it has) just like every other element in group 8A/group 18.
Answer:
The number of moles of Sr in one mole of Sr(HCO₃)₂ = 1 mole
The number of moles of H in one mole of Sr(HCO₃)₂ = 2 moles
The number of moles of C in one mole of Sr(HCO₃)₂ = 2 moles
The number of moles of O in one mole of Sr(HCO₃)₂ = 6 moles
Explanation:
The given chemical formula of the compound is Sr(HCO₃)₂
The number of atoms of Sr in the compound = 1
The number of atoms of H in the compound = 2
The number of atoms of C in the compound = 2
The number of atoms of O in the compound = 6
The number of atoms of each element present in each formula unit of Sr(HCO₃)₂ is proportional to the number of moles of each atom in one mole of Sr(HCO₃)₂
Therefore;
The number of moles of Sr in one mole of Sr(HCO₃)₂ = 1 mole
The number of moles of H in one mole of Sr(HCO₃)₂ = 2 moles
The number of moles of C in one mole of Sr(HCO₃)₂ = 2 moles
The number of moles of O in one mole of Sr(HCO₃)₂ = 6 moles.
Answer: % Errror = 11.05%
Explanation:
Percentage error is the difference between the measured value and the theoretical value as expressed in percent.
That is;
% Error =
( Theoretical value -measured value) /(Theoretical value) × 100
Theoretical value =55.2kJ
Measured value = 49.1kJ
% Error = (55.2-49.1)/(55.2) ×100
%Error = 6.1/55.2 ×100
% Error = 0.1105 ×100
% Error = 11.05
Therefore the percentage error is 11.05%
Answer:
4 g OF IODINE-131 WILL REMAIN AFTER 32 DAYS.
Explanation:
Half life (t1/2) = 8 days
Original mass (No) = 64 g
Elapsed time (t) = 32 days
Mass remaining (Nt) = ?
Using the half life equation we can obtain the mass remaining (Nt)
Nt = No (1/2) ^t/t1/2
Substituting the values, we have;
Nt = 64 * ( 1/2 ) ^32/8
Nt = 64 * (1/2) ^4
Nt = 64 * 0.0625
Nt = 4 g
So therefore, 4 g of the iodine-131 sample will remain after 32 days with its half life of 8 days.
