francium , in the Periodic table the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. making helium is the smallest element, and francium the largest.
Answer:
CO2 (s) -->Co2 (g) will be the answer
Answer: to find a cure for the common cold to produce insulin for diabetics
Explanation: It has helped many people
It's either B or D because there would be 2 coefficients of hydrogen and one of oxygen
Answer:
I) 0.0585 M
ii)6.2 g dm-3
Explanation:
The reaction equation is given as;
Na2CO3(aq) +2HCl(aq)------> 2NaCl(aq) + CO2(g) +H2O(l)
Concentration of acid CA= 0.3 M
Volume of acid VA= 3.9 cm^3
Concentration of base CB= the unknown
Volume of base VB= 10 cm^3
Number of moles of acid NA= 2
Number of moles of base NB= 1
From;
CAVA/CBVB= NA/NB
CAVANB=CBVBNA
CB= CAVANB/VBNA
substituting values;
CB= 0.3 × 3.9 × 1/ 10.0 × 2
CB= 0.0585 M
ii) mass concentration= molar concentration × molar mass
Molar mass of Na2CO3= 106 gmol-1
Mass concentration= 0.0585 × 106 = 6.2 g dm-3
