Answer:
See explanation
Explanation:
A reaction in which heat and light are produced is a combustion reaction. Combustion is said to have occurred when a substance is burnt in oxygen.
The balanced equation of the reaction is;
4Li(s) + O2(g) ------->2Li2O(s)
This reaction is exothermic because heat was produced. The reaction has a low activation energy as the metal easily burst into flames in oxygen. A catalyst is not needed in this reaction because it has a low activation energy.
According to the law of conservation of mass. Atoms are neither created nor destroyed in a chemical reaction. What this means is that in a chemical reaction, the number of atoms of each element on the left hand side must be the same as the same as the number of atoms of the same element on the right hand side.
Im not sure what the answer is unless you put the options up for the multiple choice
Before............................
m = mass of the truck traveling = 2500 kg
v = speed of the truck traveling = 75 km/h = 75 (km/h) (1000 m/ 1 km) (1 h /3600 sec) = 20.83 m/s
h = plank's constant = 6.63 x 10⁻³⁴
λ = wavelength of truck = ?
according to de broglie's principle, wavelength of truck is given as
λ = h/(mv)
inserting the values in the above equation
λ = (6.63 x 10⁻³⁴)/((2500) (20.83))
λ = 1.3 x 10⁻³⁸ m
Answer:
0.00676 M
Explanation:
A chemist prepares a solution of calcium bromide by weighing out 0.607g of calcium bromide into a 450ml volumetric flask and filling the flask to the mark with water. Calculate the concentration in mol/L of the chemist's calcium bromide solution. Be sure your answer has the correct number of significant digits.
Step 1: Given data
Mass of calcium bromide (solute): 0.607 g
Volume of solution: 450 mL
Step 2: Calculate the moles corresponding to 0.607 g of calcium bromide
The molar mass of CaBr₂ is 199.89 g/mol.
0.607 g × 1 mol/199.89 g = 0.00304 mol
Step 3: Convert the volume of solution to liters
We will use the conversion factor 1 L = 1000 mL.
450 mL × 1 L/1000 mL = 0.450 L
Step 4: Calculate the molar concentration of calcium bromide
The molarity of the solution is:
M = moles of solute / liters of solution
M = 0.00304 mol / 0.450 L
M = 0.00676 M
