During physical changes, matter always retains its chemical properties.
Answer:
The answer to your question is Molarity = 0.41
Explanation:
Data
mass of KNO₃ = 76.6 g
volume = 1.84 l
density = 1.05 g/ml
Process
1.- Calculate the molecular mass of KNO₃
molecular mass = 39 + 14 + (16 x 3) = 101 g
2.- Calculate the number of moles
101 g of KNO₃ --------------- 1 mol
76.6 g of KNO₃ ------------ x
x = (76.6 x 1) / 101
x = 0.76 moles
3.- Calculate molarity
Molarity = 
Substitution
Molarity = 
Result
Molarity = 0.41
O1Fl2
1. Assume an 100g sample, so the percentage will stay the same
2. Covert each element into their molar mass
29.6/16.00=1.8 mols of O
70.4/19.00=3.7 mols of Fl
3. Divide both by the smallest value of mol
1.8/1.8=1 O
3.7/1.8=2 Fl
4. Write the empirical formula:
O1Fl2
Answer:
6. 7870 kg/m³ (3 s.f.)
7. 33.4 g (3 s.f.)
8. 12600 kg/m³ (3 s.f.)
Explanation:
6. The SI unit for density is kg/m³. Thus convert the mass to Kg and volume to m³ first.
1 kg= 1000g
1m³= 1 ×10⁶ cm³
Mass of iron bar
= 64.2g
= 64.2 ÷1000 kg
= 0.0642 kg
Volume of iron bar
= 8.16 cm³
= 8.16 ÷ 10⁶


Density of iron bar

= 7870 kg/m³ (3 s.f.)
7.

Mass
= 1.16 ×28.8
= 33.408 g
= 33.4 g (3 s.f.)
8. Volume of brick
= 12 cm³

Mass of brick
= 151 g
= 151 ÷ 1000 kg
= 0.151 kg
Density of brick
= mass ÷ volume

(3 s.f.)
Answer:
We need 12.26 grams H2SO4
Explanation:
Step 1: Data given
Volume of a H2SO4 solution = 500 mL = 0.500 L
Concentration of the H2SO4 solution = 0.250 M
Molar mass of H2SO4 = 98.08 g/mol
Step 2: Calculate moles H2SO4
Moles H2SO4 = concentration * volume
Moles H2SO4 = 0.250 M * 0.500 L
Moles H2SO4 = 0.125 moles
Step 3: Calculate mass of H2SO4
Mass of H2SO4 = moles * molar mass
Mass of H2SO4 = 0.125 moles * 98.08 g/mol
Mass of H2SO4 = 12.26 grams
We need 12.26 grams H2SO4