Answer:
The granite block transferred <u>4080 joules</u> of energy, and the mass of the water is <u>35.84 grams</u>.
Explanation:
The equation needed to answer both parts of the question is:
Q = mcΔT
In this equation,
-----> Q = energy/heat (J)
-----> m = mass (g)
-----> c = specific heat (J/g°C)
-----> ΔT = change in temperature (°C)
<u>Part #1:</u>
First, you need to find the energy transferred from granite block using the previous equation. You have been given the mass, specific heat, and change in temperature.
Q = ? J c = 0.795 J/g°C
m = 126.1 g ΔT = 92.6 °C - 51.9 °C = 40.7 °C
Q = mcΔT
Q = (126.1 g)(0.795 J/g°C)(40.7 )
Q = 4080
<u>Part #2:</u>
Secondly, using the energy calculated in Part #1, you need to calculate the mass of the water. You have calculated the energy transferred, and have been given the specific heat and change in temperature.
Q = 4080 J c = 4.186 J/g°C
m = ? g ΔT = 51.9 °C - 24.7 °C = 27.2 °C
Q = mcΔT
4080 J = m(4.186 J/g°C)(27.2 °C)
4080 J = m(113.8592)
35.84 = m
Answer:
Option D. 30 mL.
Explanation:
Step 1:
The balanced equation for the reaction. This is given below:
HNO3 + KOH —> KNO3 + H2O
From the balanced equation above,
The mole ratio of the acid, nA = 1
The mole ratio of the base, nB = 1
Step 2:
Data obtained from the question. This include the following:
Volume of base, KOH (Vb) =.?
Molarity of base, KOH (Mb) = 0.5M
Volume of acid, HNO3 (Va) = 10mL
Molarity of acid, HNO3 (Ma) = 1.5M
Step 3:
Determination of the volume of the base, KOH needed for the reaction. This can be obtained as follow:
MaVa / MbVb = nA/nB
1.5 x 10 / 0.5 x Vb = 1
Cross multiply
0.5 x Vb = 1.5 x 10
Divide both side by 0.5
Vb = (1.5 x 10) /0.5
Vb = 30mL
Therefore, the volume of the base, KOH needed for the reaction is 30mL.
Answer:
C
Explanation:
The oxidation number of Sulphur in SO4^2- is;
x + 4(-2) = -2
x - 8 = -2
x = -2 + 8
x = 6
Now,
the oxidation number of sulphur in H2SO3 is
2 (1) + x + 3(-2) = 0
2 + x -6 = 0
-4 + x = 0
x = 4
Hence, the oxidation number of sulphur changed from +6 to +4 which signifies gain of two electrons as shown in option C.
Hydrogen sulfide = hidrogen + sulfur
6.500 g
a) 0.384 g + x
=> 6.500 = 0.384 + x => x = 6.500 - 0.384 = 6.116 g
Answer: 6.116 g of sulfur must be obtained
b) this experiment demonstrate the conservation of mass.
c) Dalton's atomic model states that the atoms cannot be created, split or be destroyed, and so in a chemical reaction the atoms rearrange but the number of each type of atoms remain constant, so the mass of each type of atoms and the total mass remain constant.
Answer:
The correct choice is E (47 neutrons, 35 protons, 36 electrons)
Explanation:
A ion of net charge -1 means that the ion wins an e-.
We dismiss options B and C.
We also dismiss option A because neutrons + protons = 81.
neutrons + protons = mass number
So we have E and C.
We see that C has 47 neutrons, 36 protons and 36 electrons and, as the atomic number matches the number of protons, we find out on the Periodic Table that the atomic number 36 represents to Krypton, a noble gas. It is impossible! A noble gas never can't be a ion of net charge.
Option E is correct, It is an isotope of Br.
Br has 35 protons (its atomic number)
47 neutrons, that's why it is an Isotope (Br has always 45 neutrons)
As usual, Br has 35 electrons, if it represents a ion of net charge -1, it menas it won 1 e-.
