化學
化學反應、化學計量、分子結構與元素性質。
-
estructuras electrón - punto y enlace - línea. 1. ¿cuáles son las fórmu…
(a) $NH_{2}OH$ (b) $AlCl_{3}$ (c) $CF_{2}Cl_{2}$ (d) $CH_{2}O$ 2. No es posible satisfacer las valencias de los átomos de una manera químicamente estable.
-
visualización de la química 1. convierta cada uno de los siguientes mod…
# Explicación: ## Paso 1: Analizar el modelo de la conina (a) Contamos los átomos de carbono (gris), hidrógeno (marfil), nitrógeno (azul). Cada átomo de carbono forma 4 enlaces, h…
-
during osmosis, water moves down its own concentration gradient. how is…
When more solutes are dissolved in solvents, the concentration of the solute increases, but per unit volume, the concentration of the solvent decreases.
-
practice it! sentoria wants to do her science project on calories in fo…
independent
-
bonus that are ______, which results in this part of the molecule being…
B. hydrogen; carbon; nonpolar; hydrophobic
-
practice it! sentoria wants to do her science project on calories in fo…
Sentoria is doing an experiment on calories of different foods. She uses the scientific method to organize the experiment. In this experiment, the outcome variable is the number o…
-
4. how might waters polarity affect the way water molecules arrange the…
Water's polarity leads to hydrogen bonding. In liquid water, hydrogen bonds are transient, and molecules move freely. During freezing, hydrogen bonds cause water molecules to form…
-
question 28 of 30 what is the product of the unbalanced combustion reac…
B. $CO_2(g)+H_2O(g)$
-
question 27 of 30 which of the following describes the reactants of a c…
C. The original substances
-
question 26 of 30 what type of reaction is shown below? sr(s) + cl2(l) …
B. Synthesis
-
question 25 of 30 why are chemical equations balanced? a. to show that …
A. To show that the total number and type of each atom does not change
-
use the figures to answer the following question. which molecule shown …
B.
-
question 24 of 30 how many carbon atoms are represented by the model be…
D. 2
-
freezing liquid you may have noticed that ice floats in water, while mo…
The water molecules in ice are arranged in a more open, less - closely - packed structure compared to liquid water.
-
question 23 of 30 what is the balanced form of the chemical equation sh…
A. $Ca(OH)_2(aq)+Na_2CO_3(aq) ightarrow CaCO_3(s)+2NaOH(aq)$
-
question 22 of 30 what is the reactant(s) in the chemical equation belo…
C. $2Al(s)+2NaOH(aq)+2H_2O(l)$
-
use the schemes to answer the question. a. -oh c. -nh₂ b. o || -c -o-h …
A. -OH
-
the molecular structures of linoleic acid and palmitic acid, two natura…
C. Palmitic acid, because the absence of carbon - carbon double bonds allows the molecules to pack closely together.
-
question 21 of 30 what is the product(s) of the reaction below? 2al(s) …
B. Solid aluminum oxide and solid iron
-
question 20 of 30 what is the balanced form of the chemical equation sh…
A. \(4Al(s)+3O_2(g) ightarrow2Al_2O_3(s)\)
-
question 19 of 30 what is the product of the unbalanced equation below?…
B. $AlBr_3(s)$
-
question 17 of 30 what type of change causes atoms to be rearranged? a.…
A. A chemical change
-
question 16 of 30 when a substance is added to water, bubbles form. how…
A. Determining that the gas produced in the reaction was different from the original substance would confirm that a chemical change took place.
-
question 15 of 30 values for the molar mass of hydrogen, chlorine, and …
A. 72.92 g
-
question 14 of 30 what is the mass of 5 moles of helium (he) atoms? the…
D. 20 g
-
question 13 of 30 which general equation shows a single - displacement …
C. A + BX → AX + B
-
question 12 of 30 which is most likely to happen during a double - disp…
D. The ions in two compounds will switch places to form two new compounds.
-
question 11 of 30 what is the balanced form of the chemical equation sh…
C. $C_6H_{12}O_6(s)+6O_2(g) ightarrow 6H_2O(l)+6CO_2(g)$
-
question 9 of 30 a structural model of adrenaline is shown below. how m…
D. 16
-
question 8 of 30 what is the mass of 2.25 moles of manganese(iv) sulfid…
D. 268 g
-
question 7 of 30 a balloon contains 7.36 g of oxygen gas (o₂). how many…
A. $1.38\times 10^{23}$ molecules
-
question 6 of 30 what is the molarity of 820 ml of ki solution that con…
D. 0.27 mol/L
-
question 5 of 30 how does the number of products in a synthesis reactio…
C. The number of products is less than the number of reactants.
-
question 4 of 30 which of the following is an example of a chemical cha…
D. Sugar breaking down into water and carbon when it is heated
-
question 3 of 30 if a reaction occurs, what will be the products of the…
D. No reaction will occur.
-
question 2 of 30 if a precipitation reaction occurs, what will be the p…
C. $PbSO_4(s)+KNO_3(aq)$
-
question 1 of 30 which type of molecular model shows all the atoms and …
D. Structural
-
chemical company makes two brands of antifreeze. the first brand is 40%…
First brand: 150 gallons Second brand: 30 gallons
-
what is one of the characteristics of the troposphere? low air pressure…
high density of air molecules
-
which statement is true about the following molecule? h h c = c ch3 ch3…
It is a cis isomer.
-
part c - lo 3. describe and differentiate psychological disorders, incl…
feeling extreme fatigue and irritability during the fall and winter months
-
part h (8 of 8) this pair of molecules are ____. cis - trans isomers (g…
C. identical
-
chemical group structure hydroxyl (may be written ho—) in a hydroxyl gr…
The amino group is most likely to gain a proton.
-
a substance with a reported melting point of 134 - 136 °c melts at 128 …
The sample contains impurities
-
multiple choice 1 point which factor most strongly determines the melti…
Molecular structure and crystal packing
-
match each procedural step with its purpose. initial rapid heating to ~…
Initial rapid heating to ~20 °C below expected melting point: Helps estimate approximate melting range Powdering the sample: Ensures uniform heat transfer Filling only 2 - 3 mm of…
-
match each compound with its correct melting point: benzoic acid benzop…
Benzoic acid: ~122°C Benzophenone: ~47°C Naphthalene: ~80°C Acetanilide: ~114°C
-
complete the text with the better adverbial conjunction. one effect of …
Accordingly
-
6 multiple answer 1 point which of the following statements about melti…
A. It is caused by impurities disrupting the crystal lattice. B. It depends on the number of solute particles in the molten phase. C. It can lead to a sharp eutectic temperature i…
-
5 multiple choice 1 point moisture in a sample affects melting point by…
A. Causing melting point depression and broadening
-
multiple choice 1 point if a mixture of benzoic acid (122 °c) and napht…
The mixture shows melting point depression
-
3 multiple choice 1 point the sharp melting range of a pure solid is ty…
A. 0.5 - 2°C
-
question 25 of 25 which sentence best describes what happens when a neu…
C. The protons pull harder on the remaining electrons.
-
2 multiple choice 1 point which of the following best describes the ter…
The temperature at which the sample starts and finishes melting
-
question 24 of 25 which molecule can form hydrogen bonds with others li…
C. $NH_3$
-
the purpose of the mixed melting point test is to: purify the sample ra…
C. Identify an unknown by comparison with a known compound
-
question 23 of 25 which of the following is a binary compound? a. nh4+ …
B. CaO
-
question 22 of 25 which molecule or ion has a trigonal planar shape? a.…
C. $SO_3$
-
question 21 of 25 what is described by the vsepr theory? a. the outside…
C. The arrangement of atoms in a molecule
-
question 20 of 25 what is the correct electron configuration for an ele…
D. \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{5}\)
-
question 19 of 25 how many electrons can the s orbital hold? a. 2 b. 10…
A. 2
-
question 18 of 25 how does electronegativity affect the polarity of the…
B. The more electronegative atom will make its end of the bond more negative.
-
question 17 of 25 which bond is a very strong dipole - dipole force? a.…
D. A hydrogen bond
-
question 16 of 25 how is the atomic number related to core electrons? a…
D. The number of valence electrons plus core electrons is the atomic number.
-
which situation would most likely cause a person to feel devastated? ba…
No one shows up for Joshua's thirteenth birthday party (disappointed)
-
question 15 of 25 how is the oxidation state of a transition metal dete…
A. A Roman numeral placed after the transition metal identifies its oxidation state.
-
question 14 of 25 what does a subscript indicate in a chemical formula?…
A. The number of atoms of that element in the molecule
-
question 13 of 25 which of the following has the smallest radius? a. rb…
C. K+
-
question 12 of 25 what causes a molecule to have a bent shape instead o…
D. Lone electron pairs pushing the bonding electrons out of line
-
question 11 of 25 how many carbon atoms are in a molecule of table suga…
D. 12
-
question 10 of 25 in which situation would hydrogen bonding be present?…
A. When hydrogen is attached to N, F, or O
-
question 9 of 25 what is the correct formula for the compound formed by…
C. $Ca(NO_{2})_{2}$
-
question 8 of 25 which sentence describes two atoms that form an ionic …
C. The difference in their electronegativities is greater than 1.7.
-
heather tutors chemistry. for each hour that she tutors, she earns 30 d…
Equation: $A = 30H$ Amount Heather earns for 17 hours: 510 dollars
-
question 7 of 25 what is the general trend in electronegativity as you …
C. Electronegativity increases.
-
question 6 of 25 what kind of compounds are named using prefixes? a. tr…
C. Covalently bonded molecules
-
question 5 of 25 what are orbitals? a. areas within an energy level tha…
A. Areas within an energy level that are occupied by electrons
-
when dissolved in water, the chemical compound h₂so₄ releases h⁺. based…
A. an acid
-
15/15 energy form characterized by the flow of electrons elastic electr…
electrical
-
question 4 of 25 which term describes this molecular shape? x a x x a. …
A. Trigonal planar
-
nuclear power plants start with what energy form? nuclear fission radia…
A. nuclear fission
-
question 3 of 25 which of these elements has the smallest atomic radius…
D. Br
-
question 2 of 25 in what order do electrons fill orbitals? a. electrons…
A. Electrons fill orbitals in order of increasing orbital energy.
-
question 1 of 25 what is required for two atoms to share electrons equa…
D. The two atoms must be of the same element.
-
which are true based on daltons atomic theory. select all that apply. a…
- Atoms of oxygen and those of hydrogen can combine to make water. - A piece of pure gold is made up of really small pieces called atoms. - All the atoms of a pure piece of gold a…
-
energy form based on the movement of particles within an object elastic…
thermal
-
question 10 of 10 when food is exposed to air, it can lose electrons. t…
A. Free radicals
-
question 9 of 10 which of these is an example of food engineering? a. l…
D. Using fertilizer on crops to increase their yield
-
identifying variables in a hypothesis identify the variables in this hy…
The independent variable is cigarette use. The dependent variable is lung function.
-
batteries, food, and gasoline have which form of energy? chemical radia…
chemical
-
question 5 of 10 which of the situations below describes an ethical dil…
A. One pesticide is used to protect a crop from being destroyed, but studies have linked it to thyroid disorders.
-
light bulbs and the sun are examples of which form of energy? mechanica…
B. radiant
-
a reference sample of a binary compound has a mass ratio of elements th…
191.43g Cl : 55.75g P 106.35g Cl : 30.97g P 53.2g Cl : 15.5g P
-
what is energy? energy in motion the ability to do work or cause change…
the ability to do work or cause change
-
talking and hearing the sound from a tv/radio are examples of which for…
C. mechanical (sound)
-
3. ¿cómo es útil la densidad para identificar sustancias desconocidas?
La densidad es útil porque es una propiedad característica de cada sustancia. Al medir la masa y el volumen de una sustancia desconocida y calcular su densidad, se puede comparar …
-
question 10 of 10 what determines the ratio of ions in an ionic compoun…
D. The charges on the ions
-
energy form stored in bonds between atoms and molecules chemical therma…
1. chemical
-
question 9 of 10 which of the following is the correct formula for copp…
D. $CuF_2$
-
review the fourth paragraph. however, the science that explains why som…
It explains why some people might not enjoy roller coasters.