Answer:
x = 3 and y= 2
Explanation:
Given equations:
8x - 3y = 18 - ---- (I)
5x + 6y = 27 -------(II)
Solve this problem by elimination;
In the elimination method, we simply find a common term that can make one of the variables in the two equation the same. Then we either add or subtract to remove the variable.
Mulitply equation (i) by 5 to give equation III
Mulitply equation (II) by 8 to give equation IV
5(8x - 3y) = 5(18) ------- III
8(5x + 6y) = 8(27) ------- IV
40x - 15y = 90------- III
40x + 48y = 216 ------- IV
Subtract equation III and IV;
-15y - 48y = 90 - 216
- 63y = -126
y = 2
Solve for x;
40x - 15y = 90;
40x - 15(2) = 90
40x - 30 = 90
40x = 90 + 30
40x = 120
x = 3
A student observes that instant tea dissolves more rapidly in a cup of 250 mL of stirred hot water than in a cup of 250 mL of stirred cold water. Which is the most relevant hypothesis that the student could develop based on this observation?
A.
Volume affects the rate that instant tea dissolves in a solvent.
B.
Temperature affects the rate that instant tea dissolves in water.
C.
Stirring affects the rate that instant tea dissolves in water.
D.
Pressure affects the rate that instant tea dissolves in water.
Please answer my question!
Answer:
B
Explanation:
In this question, there is no mention of pressure, so we can eliminate answer D. In both cups, it mentions they contain 250 mL of water and both are stirred, so these would be constants. The only difference between the cups is temperature, so temperature must affect the rate that instant tea dissolves in water. Therefore the answer is B.
You will learn in this course that organic compounds have covalent bonds with a significant amount of energy stored in them. This is why we burn fossil fuels to generate energy to heat our homes or drive our cars. Given this information, which of the compounds listed below would you expect to have the most energy is its carbon-carbon bond?
Answer:
See explanation
Explanation:
This question is obviously supposed to be a multiple choice question but the options are missing.
However, the question intends to test the student's knowledge about combustion of fossil fuels. Fossil fuels are mostly composed of hydrocarbons of different chain lengths.
The longer the chain length, the greater the energy released when the compound is burnt since there are more energy stored in its bonds.
Hence, the correct answer to this question will be the option that contains the greatest number of C-C and C-H bonds.
50 POINTS: PLEASE ANSWER AS QUICK AS POSSIBLE!
Question:
After getting their results in, a group of scientists went back and looked at their study. As planned, their experiment consisted of three groups. The first group received a new medicine at a normal dose, the second group received the medicine at half the dose, and the third group received the medicine at twice the dose.
Which of the following best describes what went wrong with the scientists’ study?
Choices:
- an improper experimental procedure
- the lack of a control group
- selection bias
- human error
Explanation:
The lack of a control group
I need help in chemistry!!!!!!!!!!!
Answer:
ok whats the question dude just ask :PPPPPPPPPPPPPPPPPPPPPP
OTHERWISE EOEOEEOEOEOOEOEOEOEOEOOEOWOWOWOWOW
wow is mom upide down
Explanation:
In science class, a student is given a copper cylinder to investigate. The student measures the mass of the cylinder as 53.76 grams. The
student measures the volume of the copper as 6 cm. Which additional property of the copper can the student determine from these
measurements?
Answer:
From these two values, i.e. mass and volume, density of the copper cylinder can be calculated.
Formula of density is :
Density = Mass / volume.
Now we have mass: 53.76g and volume 6cm³
Density = 53.76 / 6
Density= 8.96 g/cm³
How many neutrons make up one of these potassium atoms?
Answer:
20
Explanation:
Oxygen atoms have six outer electrons
Write the symbol for an oxide ion.
Answer:
[tex]O^{2-}[/tex] is the symbol for an oxide ion
What is the name of this ionic compound (Fr2SO4)
Answer:
3.5: Ionic Compounds- Formulas and Names
Last updatedAug 25, 2020
3.4: An Atomic-Level Perspective of Elements and Compounds
3.6: Molecular Compounds- Formulas and Names
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6.9: Binary Ionic Compounds and Their Properties
6.18: Ionic Compounds Containing Polyatomic Ions
Learning Objectives
Derive names for common types of inorganic compounds using a systematic approach
Nomenclature, a collection of rules for naming things, is important in science and in many other situations. This module describes an approach that is used to name simple ionic and molecular compounds, such as NaCl, CaCO3, and N2O4. The simplest of these are binary compounds, those containing only two elements, but we will also consider how to name ionic compounds containing polyatomic ions, and one specific, very important class of compounds known as acids (subsequent chapters in this text will focus on these compounds in great detail). We will limit our attention here to inorganic compounds, compounds that are composed principally of elements other than carbon, and will follow the nomenclature guidelines proposed by IUPAC. The rules for organic compounds, in which carbon is the principle element, will be treated in a later chapter on organic chemistry.
Ionic Compounds
To name an inorganic compound, we need to consider the answers to several questions. First, is the compound ionic or molecular? If the compound is ionic, does the metal form ions of only one type (fixed charge) or more than one type (variable charge)? Are the ions monatomic or polyatomic? If the compound is molecular, does it contain hydrogen? If so, does it also contain oxygen? From the answers we derive, we place the compound in an appropriate category and then name it accordingly.
Compounds Containing Only Monatomic Ions
The name of a binary compound containing monatomic ions consists of the name of the cation (the name of the metal) followed by the name of the anion (the name of the nonmetallic element with its ending replaced by the suffix –ide). Some examples are given in Table 3.5.2 .
Table 3.5.1 : Names of Some Ionic Compounds
NaCl, sodium chloride Na2O, sodium oxide
KBr, potassium bromide CdS, cadmium sulfide
CaI2, calcium iodide Mg3N2, magnesium nitride
CsF, cesium fluoride Ca3P2, calcium phosphide
LiCl, lithium chloride Al4C3, aluminum carbide
Compounds Containing Polyatomic Ions
Compounds containing polyatomic ions are named similarly to those containing only monatomic ions, except there is no need to change to an –ide ending, since the suffix is already present in the name of the anion. Examples are shown in Table 3.5.2 .
Table 3.5.2 : Names of Some Polyatomic Ionic Compounds
KC2H3O2, potassium acetate (NH4)Cl, ammonium chloride
NaHCO3, sodium bicarbonate CaSO4, calcium sulfate
Al2(CO3)3, aluminum carbonate Mg3(PO4)2, magnesium phosphate
Ionic Compounds in Your Cabinets
Ionic Compound Use
NaCl, sodium chloride ordinary table salt
KI, potassium iodide added to “iodized” salt for thyroid health
NaF, sodium fluoride ingredient in toothpaste
NaHCO3, sodium bicarbonate baking soda; used in cooking (and as antacid)
Na2CO3, sodium carbonate washing soda; used in cleaning agents
NaOCl, sodium hypochlorite active ingredient in household bleach
CaCO3 calcium carbonate ingredient in antacids
Mg(OH)2, magnesium hydroxide ingredient in antacids
Al(OH)3, aluminum hydroxide ingredient in antacids
NaOH, sodium hydroxide lye; used as drain cleaner
K3PO4, potassium phosphate food additive (many purposes)
MgSO4, magnesium sulfate added to purified water
Na2HPO4, sodium hydrogen phosphate anti-caking agent; used in powdered products
Na2SO3, sodium sulfite preservative
Table 3.5.3 : Names of Some Transition Metal Ionic Compounds
Transition Metal Ionic Compound Name
FeCl3 iron(III) chloride
Hg2O mercury(I) oxide
HgO mercury(II) oxide
Cu3(PO4)2 copper(II) phosphate
Naming Ionic Compounds
Name the following ionic compounds, which contain a metal that can have more than one ionic charge:
Fe2S3
CuSe
GaN
CrCl3
Ti2(SO4)3
Solution
The anions in these compounds have a fixed negative charge (S2−, Se2− , N3−, Cl−, and SO2−4 ), and the compounds must be neutral. Because the total number of positive charges in each compound must equal the total number of negative charges, the positive ions must be Fe3+, Cu2+, Ga3+, Cr4+, and Ti3+. These charges are used in the names of the metal ions:
iron(III) sulfide
copper(II) selenide
gallium(III) nitride
chromium(III) chloride
titanium(III) sulfate
Exercise 3.5.1
Write the formulas of the following ionic compounds:
(a) chromium(III) phosphide
(b) mercury(II) sulfide
(c) manganese(II) phosphate
(d) copper(I) oxide
(e) chromium(VI) fluoride
Answer
(a) CrP; (b) HgS; (c) Mn3(PO4)2; (d) Cu2O; (e) CrF6
Explanation:
The given compound is francium sulfate.
Explanation:
While naming ionic compounds :
First, write the name of cation Then after that name of the anion.Given
The molecule formula of a compound[tex]Fr_2SO_4[/tex]:
To find:
The name of the given compound formula
Solution:
Cation in formula = [tex]Fr^+[/tex] = Francium cation
Anion in the formula= [tex]SO_4^{-2}[/tex] = Sulfate anion
So, the name of the given compound is francium sulfate.
Learn more about the naming of compounds here:
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Which description applies to a physical property? Choose the correct answer
O depends directly on the amount of the substance present
O examines changes in the composition and structure of matter
O measured or observed without changing the identity and composition of matter
O determined by changing the identity of a substance and observing how it reacts
Answer:
the third one, measured or observed without changing the identity and composition of matter. because physical property does not under go any change but can be put back.
Which RNA strand would match with this DNA strand?
AGGCTAAT
What is the DNA strand? You have not named it.
Dilute hydrochloric acid reacts with sodium
2HCl(aq) + Na2CO3(aq) + 2NaCl(aq) + H2O(l) + CO2(g)
A Explain why effervescence is seen during the reaction.
Answer:
Because the reaction releases CO2 gas
Explanation:
therefore creating an effervecence within the solution as the carbonate dissociates
Which statement desrcribes an intensive property of matter? -it is the same for every sample of a single substance -it depends on how a substance was formed -it is the same for every sample of every substances -it depends on the amount of substances present
Answer:
The statement which describes an intensive property of matter is - :
it is the same for every sample of a single substance.
Explanation:
It is the same for every sample of a single substance. -: Since a substance 's intense property does not depend on either mass or volume, it is the same for each sample of a single substance. Hence , this statement is correct .It depends on how a substance was formed -: Intensive property do not depend upon the amount of the substance or the formation of the sample . Therefore this statement ifs wrong about intensive property .It is the same for every sample of every substances -: This is not possible to be for every sample of the substance , a every substance have different qualities. Hence this statement is also incorrect.it depends on the amount of substances present -: This is the characteristic of a extensive property of matter that relies on the amount of the material/substance. This assertion is, therefore, not valid.Hence , the correct option is A (it is the same for every sample of a single substance).
what is ch2cl2 bond angle?
Answer:
109.5
Explanation:
It's a tetrahedreal with four bonds
Which of the following is false regarding supersonic speed?
Question 10 options:
When an object reaches supersonic speed a sonic boom will occur.
When an object reaches supersonic speed it is moving faster than the speed of light.
When an object has reaches supersonic speed it breaks the sound barrier.
When an object supersonic speed it is moving faster than 343 meters/second.
Answer:
the answer is C
Explanation:
i know this one, and may YOU PLEASE MARK BRAINLIEST I ONLY NEED ONE MORE CROWN TO MOVE TO THE NEXT RANK
The
force acting on an object is the combination of
all of the individual forces acting on it.
Check it
2 SCRATCHPAD
~ Improve this questio
Answer:
Yes as you can improve The invisible to human eye force or physical force if any being applied to a object of any mass and with all individual forces as they are acting on this object
Explanation:
what does CER mean for science?
Explanation:
Claim, Evidence, Reasoning (CER) model, an explanation consists of: A claim that answers the question. Evidence from students' data. Reasoning that involves a rule or scientific principle that describes why the evidence supports the claim.
A metal object has a density of 2 g/ml. When placed in a graduated cylinder with 500 ml of water, the
water rises to 508 ml. What is the mass of the metal object?
Answer:
The answer is 16 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
density = 2 g/ml
volume = final volume of water - initial volume of water
volume = 508 - 500 = 8 mL
We have
mass = 2 × 8
We have the final answer as
16 gHope this helps you
Which further observation led Mendeleev to create the periodic table
Answer:
Mendeleev realized that the physical and chemical properties of elements were related to their atomic mass in a 'periodic' way, and arranged them so that groups of elements with similar properties fell into vertical columns in his table.
Explanation:
Please answer it correctly and explain clearly
Answer:
i think that the children will inherit the brown eyes, it is the best answer since the other things cant be inherited and he dyed his hair blonde
Explanation:
Based on the article "Will the real atomic model please stand up?," describe what Dalton's theory states about a molecule of water. Dalton's theory about compounds tells us that all water molecules have different kinds of atoms, two hydrogen atoms for every one oxygen atom.
Answer:
Follows are the solution to this question:
Explanation:
The characterization with water molecules would be that light waves are made up of 2 different types of atoms (2 hydrogen and 1 oxygen atoms), as per the Dalton theory. There are many multiple times as many atoms of hydrogen as oxygen atoms in each water molecules. For every two hydrogen atoms, all water molecules have one oxygen atom.
Answer:
Sample Response: Dalton’s theory about compounds tells us that all water molecules have different kinds of atoms, two hydrogen atoms for every one oxygen atom.
Explanation:
8. Which word best describes the element in box number 2?
a а Brittle
b Gas
С Semiconductor
d. Shiny
Answer:
gas
Explanation:
i think it might be gas
Elements in group to are cold alkaline earth metals what is most similar about alkaline earth metals how many protons and neutrons they have which Chemical properties he have how many total electrons they have which period They have most often found in
Answer:
explanations below
Explanation:
The alkaline earth metals are the 6 chemical elements that can be found in group two of the periodic table. These elements have a lot of properties in common, in the sense that they are generally shiny, reactive at standard temperature and pressure and they are also silvery-white. The elements are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra)
These metals have two electrons at their orbits, which can be easily lost to form cations (with charge +2, and an oxidation state of +2)
Below are some of their details
Name: Beryllium
Number of Protons/Electrons: 4
Number of Neutrons: 5
Name: Magnesium
Number of Protons/Electrons: 12
Number of Neutrons: 12
Name: Calcium
Number of Protons/Electrons: 20
Number of Neutrons: 20
Name: Strontium
Number of Protons/Electrons: 38
Number of Neutrons: 50
Name: Barium
Number of Protons/Electrons: 56
Number of Neutrons: 81
Name: Radium
Number of Protons/Electrons: 88
Number of Neutrons: 138
What metal is Potassium (K)?
Explanation:
Potassium is a chemical element with the symbol K and atomic number 19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure
Answer:
alkali metalExplanation:
Potassium is a chemical element with symbol K and atomic number 19. Classified as an alkali metalWhat is hydrochloride acid plus water plus salt and water
Aquanauts explore the area called?
Answer:
Inner space
Explanation:
I hope this helps
Two compounds of phosphorus and fluorine have the following
mass ratios.
Compound 1: 10.14 g fluorine for every 3.38 g phosphorus
Compound 2: 8.42 g fluorine for every 4.21 g phosphorus
Find the whole number ratio of masses of fluorine in compound
1 to compound 2.
Help me please
Answer: 3:2
Explanation: (10.14÷3.38)÷(8.42÷4.21)=1.5=3/2
Convert 122 moles of Methane to liters?
I need help again LOL.
Answer:
They require diffrent types of atoms for their makeup I belive is the answer Hope this helps
Explanation: Wow you have a lot a questions XD :D :3
Element: A substance that is made up of only one type of atom. Compound: A substance that is made up of more than one type of atom bonded together. Mixture: A combination of two or more elements or compounds which have not reacted to bond together; each part in the mixture retains its own properties.
i hope this helps
How many protons, electrons and neutrons do A nitrogen atom with atomic number 7 and mass number 14
Answer:
p =7
e = 7
n = 7
Explanation:
proton = atom number
electron = atom number - muatan
neutron = mass nimber - atomic number
Which phrase is most similar in meaning to “scientific theory”?
A. a best guess explanation
B. a rigorously tested explanation
C. an opinion of what should happen
D. a mathematical relationship
Answer:
c
Explanation:
Answer:
A. a best guess explanation
Explanation:
A scientific theory explains why something behaves the way it does and is usually backed up by different sources. They are not speculations and can be proven. Those which are speculations and are not proven are called hypothesis. A scientific theory can also be replaced, if it is found that it does not produce valid results, or if a better theory is proposed which is made of one or more old theories.