
Concept explainers
(a)
The percentage by mass of each element in salt, NaCl.
(a)

Answer to Problem 7E
Explanation of Solution
The percentage by mass of an element in a compound is defined as the percentage of total mass of that element present in the total mass or formula mass of the compound. Mass percent of any element B in compound AB is given as,
% B component = (total mass of component Bformula mass of compound AB)100 %
The formula mass of NaCl is calculated as,
Formula mass of NaCl=atomic mass of Na+atomic mass of Cl
Substitute 23.0 u for atomic mass of Na and 35.5 u for atomic mass of Cl in the above equation.
Formula mass of NaCl=23.0 u+35.5 u=58.5 u
The percentage by mass of sodium (Na) is given as,
% Na = (total mass of Naformula mass of NaCl)100 % (1)
Substitute 23.0 u for total mass of Na and 58.5 u for formula mass of NaCl in equation (1).
% Na=(23.0 u58.5 u)100 %= 39.3 %
The percentage by mass of chlorine (Cl) is given as,
% Cl = (total mass of Clformula mass of NaCl)100 % (2)
Substitute 35.5 u for total mass of Cl and 58.5 u for formula mass of NaCl in equation (2).
% Cl=(35.5 u58.5 u)100 %= 60.7 %
Conclusion:
Therefore, the percentage by mass of sodium (Na) is 39.3 % and percentage by mass of chlorine (Cl) is 60.7 % in salt, NaCl.
(b)
The percentage by mass of each element in sucrose, C12H22O11.
(b)

Answer to Problem 7E
Explanation of Solution
The percentage by mass of an element in a compound is defined as the percentage of total mass of that element present in the total mass or formula mass of the compound. Mass percent of any element B in compound AB is given as,
% B component = (total mass of component Bformula mass of compound AB)100 %
Atomic mass of carbon (C) is 12.0 u.
Atomic mass of hydrogen (H) is 1.0 u.
Atomic mass of oxygen (O) is 16.0 u.
The chemical formula of sucrose is C12H22O11, it consists of 12 atoms of carbon, 22 atoms of hydrogen and 11 atoms of oxygen.
The formula mass of sucrose, C12H22O11 is calculated as,
Formula mass of C12H22O11=[12(atomic mass of C)+22 (atomic mass of H)+11(atomic mass of O)] (3)
Substitute 12.0 u for atomic mass of C, 1.0 u for atomic mass of H and 16.0 u for atomic mass of O in equation (3).
Formula mass of C12H22O11=12(12.0 u)+22 (1.0 u)+11(16.0 u)=342.0 u.
The total mass of carbon (C) atoms is,
total mass of C = 12(atomic mass of carbon)
Substitute 12.0 u for atomic mass of carbon.
total mass of C = 12(12.0 u)=144.0 u
The total mass of hydrogen (H) atoms is,
total mass of H = 22(atomic mass of hydrogen)
Substitute 1.0 u for atomic mass of hydrogen.
total mass of C = 22(1.0 u)=22.0 u
The total mass of oxygen (O) atoms is,
total mass of O = 12(atomic mass of oxygen)
Substitute 16.0 u for atomic mass of oxygen.
total mass of O = 11(16.0 u)=176.0 u
The percentage by mass of carbon (C) is given as,
% C = (total mass of Cformula mass of C12H22O11)100 % (4)
Substitute 144.0 u for total mass of C and 342.0 u for formula mass of C12H22O11 in equation (4).
% C = (144.0 u342.0 u)100 %=42.1 %
The percentage by mass of hydrogen (H) is given as,
% H = (total mass of H formula mass of C12H22O11)100 % (5)
Substitute 22.0 u for total mass of H and 342.0 u for formula mass of C12H22O11 in equation (5).
% Cl=(22.0 u342.0 u)100 %= 6.4 %
The percentage by mass of oxygen (O) is given as,
% O = (total mass of O formula mass of C12H22O11)100 % (6)
Substitute 176.0 u for total mass of O and 342.0 u for formula mass of C12H22O11 in equation (6).
% O=(176.0 u342.0 u)100 %= 51.5 %
Conclusion:
Therefore, the percentage by mass of carbon (C) is 42.1 %, the percentage by mass of hydrogen (H) is 6.4 % and percentage by mass of oxygen (O) is 51.5 % in sucrose, C12H22O11.
Want to see more full solutions like this?
Chapter 12 Solutions
An Introduction to Physical Science
- You are standing a distance x = 1.75 m away from this mirror. The object you are looking at is y = 0.29 m from the mirror. The angle of incidence is θ = 30°. What is the exact distance from you to the image?arrow_forwardFor each of the actions depicted below, a magnet and/or metal loop moves with velocity v→ (v→ is constant and has the same magnitude in all parts). Determine whether a current is induced in the metal loop. If so, indicate the direction of the current in the loop, either clockwise or counterclockwise when seen from the right of the loop. The axis of the magnet is lined up with the center of the loop. For the action depicted in (Figure 5), indicate the direction of the induced current in the loop (clockwise, counterclockwise or zero, when seen from the right of the loop). I know that the current is clockwise, I just dont understand why. Please fully explain why it's clockwise, Thank youarrow_forwardA planar double pendulum consists of two point masses \[m_1 = 1.00~\mathrm{kg}, \qquad m_2 = 1.00~\mathrm{kg}\]connected by massless, rigid rods of lengths \[L_1 = 1.00~\mathrm{m}, \qquad L_2 = 1.20~\mathrm{m}.\]The upper rod is hinged to a fixed pivot; gravity acts vertically downward with\[g = 9.81~\mathrm{m\,s^{-2}}.\]Define the generalized coordinates \(\theta_1,\theta_2\) as the angles each rod makes with thedownward vertical (positive anticlockwise, measured in radians unless stated otherwise).At \(t=0\) the system is released from rest with \[\theta_1(0)=120^{\circ}, \qquad\theta_2(0)=-10^{\circ}, \qquad\dot{\theta}_1(0)=\dot{\theta}_2(0)=0 .\]Using the exact nonlinear equations of motion (no small-angle or planar-pendulumapproximations) and assuming the rods never stretch or slip, determine the angle\(\theta_2\) at the instant\[t = 10.0~\mathrm{s}.\]Give the result in degrees, in the interval \((-180^{\circ},180^{\circ}]\).arrow_forward
- What are the expected readings of the ammeter and voltmeter for the circuit in the figure below? (R = 5.60 Ω, ΔV = 6.30 V) ammeter I =arrow_forwardsimple diagram to illustrate the setup for each law- coulombs law and biot savart lawarrow_forwardA circular coil with 100 turns and a radius of 0.05 m is placed in a magnetic field that changes at auniform rate from 0.2 T to 0.8 T in 0.1 seconds. The plane of the coil is perpendicular to the field.• Calculate the induced electric field in the coil.• Calculate the current density in the coil given its conductivity σ.arrow_forward
- An L-C circuit has an inductance of 0.410 H and a capacitance of 0.250 nF . During the current oscillations, the maximum current in the inductor is 1.80 A . What is the maximum energy Emax stored in the capacitor at any time during the current oscillations? How many times per second does the capacitor contain the amount of energy found in part A? Please show all steps.arrow_forwardA long, straight wire carries a current of 10 A along what we’ll define to the be x-axis. A square loopin the x-y plane with side length 0.1 m is placed near the wire such that its closest side is parallel tothe wire and 0.05 m away.• Calculate the magnetic flux through the loop using Ampere’s law.arrow_forwardDescribe the motion of a charged particle entering a uniform magnetic field at an angle to the fieldlines. Include a diagram showing the velocity vector, magnetic field lines, and the path of the particle.arrow_forward
- Discuss the differences between the Biot-Savart law and Coulomb’s law in terms of their applicationsand the physical quantities they describe.arrow_forwardExplain why Ampere’s law can be used to find the magnetic field inside a solenoid but not outside.arrow_forward3. An Atwood machine consists of two masses, mA and m B, which are connected by an inelastic cord of negligible mass that passes over a pulley. If the pulley has radius RO and moment of inertia I about its axle, determine the acceleration of the masses mA and m B, and compare to the situation where the moment of inertia of the pulley is ignored. Ignore friction at the axle O. Use angular momentum and torque in this solutionarrow_forward
- An Introduction to Physical SciencePhysicsISBN:9781305079137Author:James Shipman, Jerry D. Wilson, Charles A. Higgins, Omar TorresPublisher:Cengage LearningModern PhysicsPhysicsISBN:9781111794378Author:Raymond A. Serway, Clement J. Moses, Curt A. MoyerPublisher:Cengage Learning
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning




