Description : (1) they contain free electrons Explanation: Metals typically consist of closepacked atoms, meaning that the atoms are arranged like closely packed spheres. Two packing motifs are common, one ... surrounded by six neighboring atoms. Several metals adopt both structures, depending on the temperature.
Last Answer : Helium gas is filled in ballons because (1) its atomic number is 2 (2) it is lighter than air (3) it is one of the constitutents of water (4) it is a noble gas
Description : How many atoms per unit cell are in a face-centered-cubic crystal? w) two x) four y) six z) eight
Last Answer : ANSWER: X -- FOUR
Description : Cubic crystals containing lattice points only at the corners are called: w) body centered x) face centered y) simple z) hexagonal
Last Answer : ANSWER: C-SIMPLE
Description : How many neighboring atoms are in contact with each a in a hexagonal close-packed structure?
Last Answer : ANSWER: 12
Description : Sodium chloride is an example of what kind of compound? w) ionic x) covalent y) polyatomic z) monatomic
Last Answer : ANSWER: W -- IONIC
Description : Which of the following atoms or ions would be the smallest? w) sodium atom x) magnesium atom y) singly charged sodium ion z) doubly charged magnesium ion
Last Answer : ANSWER: Z -- DOUBLY CHARGED MAGNESIUM ION
Description : When white light is passed through a double slit which of the following statements is TRUE: w) Each of the bright bands is dispersed into a spectrum x) Only the central band is dispersed into ... one are dispersed into a spectrum z) Each band has a single color different from its neighboring bands
Last Answer : ANSWER: Y -- ALL THE BRIGHT BANDS EXCEPT THE CENTRAL ONE ARE DISPERSED INTO THE SPECTRUM
Description : The equilibrium constant for the gas phase reactio A + B = C + D is 10-3. The rate of the forward reaction is 10-11 cubic centimeters per molecule per second. What is the rate constant of ... second y) 10-10 cubic centimeters per molecule per second z) 10-14 cubic centimeters per molecule per second
Last Answer : ANSWER: Z -- 10-14 CUBIC CENTIMETERS PER MOLECULE PER SECOND
Description : How many atoms of oxygen are in a glucose molecule w) 2 x) 6 y) 10 z) 12
Last Answer : ANSWER: X -- 6
Description : Solids may be considered to be either crystalline noncrystalline. The basic difference between them is that a crystal, in contrast to a noncrystal: w) has a sharp melting point x) has an irregular array of atoms y) exhibits double refraction z) has a completely regular atomic or molecular structure
Last Answer : ANSWER: Z -- HAS A COMPLETELY REGULAR ATOMIC OR MOLECULAR STRUCTURE
Description : What is the relative humidity when the absolute humidity is 3 grams per cubic meter and the air has a capacity of 12 grams per cubic meter? w) 4% x) 9% y) 25% z) 400%
Last Answer : ANSWER: Y -- 25%
Description : How many carbon atoms are there in one naphthalene molecule? w) 6 x) 8 y) 10 z) 15
Last Answer : ANSWER: Y -- 10
Description : How many carbon atoms are there in one napthalene molecule? w) 6 x) 8 y) 10 z) 15
Description : If edge length of an unit cell `=4xx10^(-8)` cm and the unit cell is a face-centered cubic with atomic mass of metal is 40 then density of the unit ce
Last Answer : If edge length of an unit cell `=4xx10^(-8)` cm and the unit cell is a face-centered cubic with atomic mass of ... /(24) `gm/ml D. `(1)/(4)` gm/litre
Description : Out of the following, the lowest packing of atoms exists in __________ crystal lattice structure. (A) Hexagonal close, packed (hcp) (B) Face centred cubic (fcc) (C) Body centred cubic (bcc) (D) Simple cubic
Last Answer : (D) Simple cubic
Description : Pick out the wrong statement. (A) Cp of monatomic gases such as metallic vapor is about 5 kcal/kg.atom (B) The heat capacity of solid inorganic substance is exactly equal to the ... isolated system (D) At absolute zero temperature, the heat capacity for many pure crystalline substances is zero
Last Answer : (C) There is an increase in entropy, when a spontaneous change occurs in an isolated system
Description : The number of octahedral void(s) per atom present in a cubic close-packed structure is (1) 4 (2) 1 (3) 3 (4) 2
Last Answer : 1
Description : A gas at 0 degrees C and at normal atmospheric pressure has a volume of 273 cubic centimeters. If it is held at constant pressure until its volume is doubled, its temperature will be which one of the ... it be w) 2 degrees Celsius x) 200 degrees Celsius y) 273 degrees Celsius z) 546 degrees Celsius
Last Answer : ANSWER: Y -- 273 DEGREES CELSIUS
Description : The earth's average density is: w) 2.82 grams per cubic centimeter x) 4.75 grams per cubic centimeter y) 5.52 grams per cubic centimeter z) 10.5 grams per cubic centimeter
Last Answer : ANSWER: Y -- 5.52 GRAMS PER CUBIC CENTIMETER
Description : The co-ordination number in simple cubic structure is (A) 4 (B) 6 (C) 8 (D) 12
Last Answer : (B) 6
Description : In a body-centered structure for cesium chloride how many nearest neighbor chloride ions surround a cesium ion?
Last Answer : ANSWER: 8
Description : The nuclei of heavy atoms generally contain: w) more electrons than neutrons x) more protons than electrons y) more neutrons than electrons z) more orbitals than electrons
Last Answer : ANSWER: Y -- MORE NEUTRONS THAN ELECTRONS
Description : Carbon atoms link together with other carbon atoms in all of the following ways EXCEPT w) networks x) chains y) ionic bonds z) rings
Last Answer : ANSWER: Y -- IONIC BONDS
Description : What is a typical spacing between atoms in a crystal, e.g., copper or rock salt? w) 0.1 Angstroms x) 2 Angstroms y) 20 Angstroms z) 100 Angstroms
Last Answer : ANSWER: B -- 2 ANGSTROMS
Description : Molecular oxygen is said to be paramagnetic. This indicates that molecular oxygen: w) is a gas at room temperature x) forms molecules containing two oxygen atoms y) has an approximate molecular weight of 32 z) has unpaired electrons
Last Answer : ANSWER: Z -- HAS UNPAIRED ELECTRONS
Description : The bond most likely to be formed when two atoms differ SOMEWHAT in their tendency to attract electrons is: w) nonpolar ionic x) polar ionic y) polar covalent z) nonpolar covalent
Last Answer : ANSWER: Y -- POLAR COVALENT
Description : In 2-butene, which of the following bonds prevents the atoms at each end of the bond from rotating with respect to each other. Is it an: w) ionic bond x) sigma bond y) strong bond z) double bond
Last Answer : ANSWER: Z -- DOUBLE BOND
Description : Which of the following pairs of numbers best represents the diameter, in nanometers, of most atoms? w) between 0.1 and 0.5 x) between 1 and 10 y) between 10 and 100 z) between 10,000 and 1,000,000
Last Answer : ANSWER: A -- BETWEEN 0.1 AND 0.5
Description : Which of the following inert gas atoms is the heaviest? w) xenon x) neon y) radon z) krypton
Last Answer : ANSWER: Y -- RADON
Description : The atoms in sugar are bound by what type of bond? w) ionic x) hydrogen y) covalent z) van der Waals
Last Answer : ANSWER: Y -- COVALENT
Description : Hydrocarbons that contain a triple bond between carbon atoms are known as: w) alkenes x) alkanes y) alkynes z) polymers
Last Answer : ANSWER: Y -- ALKYNES
Description : The triple bond between the carbon atoms causes acetylene, C2H2, to have which of the following shapes? w) trigonal planar (pron: try-gon-al) x) linear y) tetrahedral z) trigonal bipyramidal
Last Answer : ANSWER: X -- LINEAR
Description : In the common dry cell, the zinc atoms are: w) reduced at the cathode x) oxidized at the cathode y) oxidized at the anode z) reduced at the anode
Last Answer : ANSWER: Y -- OXIDIZED AT THE ANODE
Description : Which one of the following atoms has two unpaired electrons in its ground state: w) Sodium x) Calcium y) Oxygen z) Aluminum
Last Answer : ANSWER: Y -- OXYGEN
Description : Which of the following contain sp2 hybridized carbon atoms? w) alkanes x) alkenes y) alkynes z) cycloalkanes
Last Answer : ANSWER: X -- ALKENES
Description : The noble gases have low boiling points because: w) their ionization potentials are very low x) only weak Van der Waals forces hold the atoms together y) they are produced by the fractional distillation of liquid air z) they have eight electrons in the outer shell
Last Answer : ANSWER: X -- ONLY WEAK VAN DER WAALS FORCES HOLD THE ATOMS TOGETHER
Description : The word atom is from a Greek word meaning: w) small x) indivisible y) unseen z) visible
Last Answer : ANSWER: X -- INDIVISIBLE
Description : What is the process by which an atom gains electrons? w) Reduction x) Neutralization y) Electrolysis z) Oxidation
Last Answer : ANSWER: W -- REDUCTION
Description : Which of the following scientists first determined the atomic number of an atom by use of X-rays? Is it: w) Millikan x) Planck y) Thompson z) Moseley
Last Answer : ANSWER: Z -- MOSELEY
Description : For which molecule can the bonding be described in terms of sp3 hybrid orbitals of the central atom? w) CH4 x) SF6 y) BF3 z) PCL5
Last Answer : ANSWER: B -- CH4
Description : Which of the following terms refers to the energy released when an electron is added to a neutral atom? w) electrovalence x) electron affinity y) electroconductance z) none of these
Last Answer : ANSWER: X -- ELECTRON AFFINITY
Description : A compound which contains two ring structures havi one common carbon atom is known as a: w) spiro-compound x) nonpolar compound y) interstitial compound z) inner compound
Last Answer : ANSWER: W -- SPIRO-COMPOUND
Description : Which of the following describes the orientation of bonds in an sp3 hybridized atom? w)triagonal x)linear y)tetrahedral z)planar
Last Answer : ANSWER: Y -- TETRAHEDRAL
Description : Which of the following terms refers to the number of molecules or ions attached to a central metallic atom? w) coordination number x) connection number y) bonding number z) none of these
Last Answer : ANSWER: W -- COORDINATION NUMBER
Description : In Fig. 7.21, AC = AE, AB = AD and BAD = EAC. Show that BC = DE. -Maths 9th
Last Answer : It is given that ∠BAD=∠EAC ∠BAD+∠DAC=∠EAC+∠DAC [add ∠DAC on both sides] ∴∠BAC=∠DAE In △BAC and △DAE AB=AD (Given) ∠BAC=∠DAE (Proved above) AC=AE (Given) ∴△BAC≅△DAE (By SAS congruence rule) ∴BC=DE (By CPCT)
Description : Nitric acid is made from air and water by the: w) Haber process x) Contact process y) Castner process z) Arc process
Last Answer : ANSWER: Z -- ARC PROCESS
Description : How many atoms are there per unit cell in a body centred cubic lattice system? (A) 6 (B) 5 (C) 3 (D) 2
Last Answer : (D) 2
Description : If the half-life of a radioisotope is 2 days, after how many days is the quantity reduced to 12.5% of its original amount? w) 4 days x) 6 days y) 8 days z) 10 days
Last Answer : ANSWER: X -- 6 DAYS
Description : Estimate the number of atoms comprising a silicon chip that is 0.2 millimeters by 0.2 millimeters by 0.1 millimeters, given that the density of silicon is 2.34 grams per cubic centimeter, the number of atoms in a gram-weight is approximately 6 x 1023 atoms, and the atomic weight of silicon is 28:
Last Answer : ANSWER: 2 x 1017
Description : Which one of the following metals is essential to the structure and functioning of hemoglobin? w) copper x) magnesium y) tin z) iron
Last Answer : ANSWER: Z -- IRON