Answer:
The solution is given below.
Explanation:
Speed = Distance(m)/Time(sec.)
Distance traveled = 150 m
Time taken = 3.5 seconds
Speed of car = 150/3.5 = 42.86 m/s
So the car traveled at a speed of 42.86 m/s.
(A) Gamma waves have the highest energy
Answer:
6.53g of K₂SO₄
Explanation:
Formula of the compound is K₂SO₄
Given parameters:
Volume of K₂SO₄ = 250mL = 250 x 10⁻³L
= 0.25L
Concentration of K₂SO₄ = 0.15M or 0. 15mol/L
Unknown:
Mass of K₂SO₄ =?
Methods:
We use the mole concept to solve this kind of problem.
>>First, we find the number of moles using the expression below:
Number of moles= concentration x volume
Solving for number of moles:
Number of moles = 0.25 x 01.5
= 0.0375mole
>>Secondly, we use the number of moles to find the mass of K₂SO₄ needed. This can be obtained using the expression below:
Mass(g) = number of moles x molar mass
Solving:
To find the molar mass of K₂SO₄, we must know the atomic mass of each element in the compound. This can be obtained using the periodic table.
For:
K = 39g
S = 32g
O = 16g
Molar mass of K₂SO₄ = (39x2) + 32 + (16x4)
= 78 +32 + 64
= 174g/mol
Using the expression:
Mass(g) = number of moles x molar mass
Mass of K₂SO₄ = 0.0375 x 174 = 6.53g
KBr + H2O = KOH + Br2 + H2
So we know that we need a 2 on the left of kbr so it would equal the right Br.
=2KBr
now put a 2 in front of KOH since we need a 2k on right side
Now we put a 2 infront of H2O which wil make 4 h's and 2 o's
2h2o
now it is balanced
2KBr + 2H2O = 2KOH + Br2 + H2
