Answer:
C
Explanation:
Most atoms follow the octet rule meaning they need ------ electrons to fill their valence shells. One important exception is H which only needs ------------ electrons to fill its valence shell.
full they blank
Answer:
The octet rule means that atoms need a total of 8 valence electrons to fill their valence shell. Hydrogen only needs two to fill its valence shell.
Explanation:
All atoms except for hydrogen can hold a total of 8 valence electrons in their outer energy levels (2 in the s level, 6 in the p level). Hydrogen only has two electrons total, so it does not require more than the s level and two electrons to have a full valence.
What is the pH of a 0.08 M solution of Ca(OH),?
Answer:
pH = 12.20
Explanation:
Ca(OH)2 is a strong base, so it dissociates completely. A 0.08 M solution of Ca(OH)2 is 0.16 M OH-, since every mole of Ca(OH)2 has 2 OH-.
Calculate pOH using [OH-] = 0.16 M
pOH = -log(0.16) = 0.80
pH = 14 - pOH = 14 - 0.80 = 12.20
Taking into account the definition of pH and pOH, the pH of a 0.08 M solution of Ca(OH)₂ is 13.21
pHFirst of all, pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.
The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions or H₃O⁺:
pH= - log [H⁺]= - log [H₃O⁺]
pOHSimilarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:
pOH= - log [OH⁻]
Relationship between pH and pOHThe following relationship can be established between pH and pOH:
pOH + pH= 14
This caseA strong base is one that dissociates completely in water, that is, it contributes the maximum number of OH- ions.
Ca(OH)₂ is a strong base that for each Ca²⁺ cation there are two OH⁻ anions and in which for each mole of Ca(OH)₂ two moles of OH⁻ are formed.
So: [OH⁻]= 2×[Ca(OH)₂]
[OH⁻]= 2×0.08 M
[OH⁻]= 0.16 M
Replacing in the definition of pOH:
pOH= - log (0.16 M)
Solving:
pOH= 0.79
Finally, considering the relationship between pH and pOH:
0.79 + pH= 14
pH= 14 - 0.79
pH= 13.21
In summary, the pH of a 0.08 M solution of Ca(OH)₂ is 13.21
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what is the first element in the periodic table?
Answer:
the first element on the table is Hydrogen
How many moles of Ag can be obtained from 2.77 moles Cu using the following
balanced reaction?
2AgNO3
+ Cu
Cu(NO3)2
+ 2Ag
Answer:
2.77×2= 5.4 mol Ag can be obtained
An antacid tablet weighs 2.10 grams. It requires 45.67 mL of 0.105 M of HCI solution to react completely with the carbonate present in the tablet. Determine the mass of CaCO3 present in the tablet?
Answer:
≅ 0.240 grams (3 sig. figs.)
Explanation:
Rxn: CaCO₃ + 2HCl => CaCl₂ + H₂O + CO₂
Given: ?g 45.67ml(0.105M)
= 0.04567L x 0.105 mole/L
= 0.0048 mole HCl
Rxn ratio for CaCO₃ to HCl is 1:2
∴ moles CaCO₃ consumed = 1/2 of moles HCl used
=> 1/2(0.0048)mole CaCO₃ used = 0.0024 mole CaCO₃
mass CaCO₃ = 0.0024 mole CaCO₃ x 100.09 grams CaCO₃/mole CaCO₃
= 0.23998 grams CaCO₃ (calculator answer)
≅ 0.240 grams (3 sig. figs.)
Fill in the missing information:
1. Complete Nuclear Symbol ________
2. Atomic # ________
3. Mass number ________
# Protons 22
# Electrons 18
# Neutrons 26
4. Charge _________
Answer: 1. Complete Nuclear Symbol : [tex]_{22}^{48}{Ti^{4+}}[/tex]
2. Atomic number : 22
3. Mass number : 48
4. Charge : 4 +
Explanation:
Atomic number is equal to the number of protons.
Mass number is the sum of number of neelectrons. utrons and number of protons.
Given : no of protons = 22 , thus atomic number = 22
Mass number = number of neutrons + number of protons
Mass number = 26 + 22 = 48
Also for a neutral atom , the number of protons is equal to the number of electrons. But here electrons are 4 less than protons, which means the atom has lost 4 electrons and thus will have a charge of 4+.
The atomic number is specific to an element, and the element with atomic number 22 is Titanium (Ti). The representation is [tex]_{22}^{48}{Ti^{4+}}[/tex]
assign an oxidation number to each element in the following species. H2O
Answer:
the oxidation number of hydrogen is +2, while oxygen is -2
Litmus is an example of an indicator, a substance that changes color depending on its pH.
a. True
b. False
5. Choose the best description of a reversible reaction.
a reaction that occurs in both directions at the same time
a reaction that has used up all the reactants and has stopped
a reaction that can only proceed to the right
a reaction that can only proceed to the left
Answer:
A reaction that can only move towards the right.
Explanation:
For a reversible reaction when one of the products of the reaction is removed the reaction moves towards right hand side. More and more reactants will be converted into products. This will nullify the effect of removal of product.
Which two substances are covalent compounds?
A. C6H12O6(s) and KI(s)
B. C6H1206(s) and HCl(g)
C. KI(S) and NaCl(s)
D. NaCl(s) and HCl(g)
Answer:
Option B is correct: C6H1206(s) and HCl(g)
Is that flirting? I'm not sure and I really need to know-
Answer:
I mean ig it is, but i dk
Explanation:
A mixture results in a ___________________________ change.
Answer:
physical
Explanation:
Why glucose (monosaccharide) and maltose (disaccharide) give positive Benedict test?
Answer:
please give me brainlist and follow
Explanation:
Substance in water + 3 mL Benedict's solution, then boil for few minutes and allow to cool. The common disaccharides lactose and maltose are directly detected by Benedict's reagent because each contains a glucose with a free reducing aldehyde moiety after isomerization.
Glucose and maltose give a positive Benedict test because they have a free carbonyl group to undergo oxidation.
Explanation:
The monosaccharides are sugars that cannot be further hydrolyzed into simpler sugars like glucose, fructose, ma, etc.The disaccharides are sugars that on hydrolysis give two monosaccharide units like sucrose, lactose, maltose, etc.The polysaccharides are sugars that on hydrolysis give more than two monosaccharide units like sucrose, lactose, maltose, etc.Reducing sugars are which have a free carbonyl group that oxidizes into a carboxylic acid and reduces Benedict reagent like glucose, maltose, etc.Non-reducing sugars which don't have a free carbonyl group like sucrose, all polysaccharides, etc.Benedict test is a chemical test performed to test the presence of reducing sugars.The Benedict reagent is a complex made up of sodium citrate, sodium carbonate, and copper sulfate pentahydrate.The positive test for reducing sugar will be the red coloration of the solution due to the formation of copper(II) oxide.So, from this, we can conclude that glucose and maltose give a positive Benedict test because they have a free carbonyl group to undergo oxidation.
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Determine the number of atoms in 3.14 g gold
based on their scientific names, you know the cats felis catus and felis bieti do not belong to the same
A. family
B. species
C. zoo
D. domain
In an ecosystem, based on their scientific names, you know the cats felis catus and felis bieti do not belong to the same species.
What is an ecosystem?
Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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What is the pressure (in atm) in a 5.00 L tank with 9.00 grams of oxygen gas at 350 K?
Answer:
1.61 atm
Explanation:
Using general gas law equation as follows:
PV = nRT
Where;
P = pressure (atm)
V = volume (L)
n = number of moles (mol)
R = gas law constant (0.0821 Latm/molK)
T = temperature (K)
From the information provided in this question,
V = 5.00L
T = 350K
mass of O2 = 9.00g
Using mole = mass/molar mass
Molar mass of O2 = 16(2) = 32g/mol
mole = 9/32
mole = 0.28mol
Using PV = nRT
P = nRT/V
P = 0.28 × 0.0821 × 350/5
P = 8.0458/5
P = 1.609
Pressure = 1.61 atm
The pressure of the oxygen gas at the given temperature and volume is 1.61 atm.
The given parameters;
volume of the gas, V = 5 Lmass of the oxygen gas, m = 9 gtemperature of the gas, T = 350 KThe number of the moles of the given gas is calculated as follows;
[tex]moles = \frac{m}{M} \\\\moles = \frac{9}{32} \\\\moles = 0.28 \ mol[/tex]
The pressure of the gas is calculated as follows;
[tex]PV = nRT\\\\P = \frac{nRT}{V} \\\\P = \frac{0.28 \times 0.0821 \times 350}{5} \\\\P = 1.61 \ atm[/tex]
Thus, the pressure of the oxygen gas at the given temperature and volume is 1.61 atm.
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Does anyone know the answer I need help
Answer:
Can you put other picture because the picture is blurry? please
Explanation:
Aqueous hydrochloric acid HCl will react with solid sodium hydroxide NaOH to produce aqueous sodium chloride NaCl and liquid water H2O. Suppose 15.7 g of hydrochloric acid is mixed with 27. g of sodium hydroxide. Calculate the maximum mass of sodium chloride that could be produced by the chemical reaction.
Answer:
25.155 gram
Explanation:
HCl(aq.) + NaOH(aq.) ⇒ NaCl + H2O
According the above equation equal number of moles of reactant are producing same number of moles of products.
Now, no. mole of HCl = 15.7/(1+35.5) = 0.43 moles
no. of moles of NaOH = 27/(23+16+1) = 0.675 moles
Since the amount of sodium hydroxide exceeds the amount of hydrochloric acid, the maximum amount of each substance participating in the reaction is HClν ν 0.43 moles .Therefore, the maximum amount of NaCl that can be produced is as follow
= (23+35.5)×0.43 = 25.155 gram
Which of the following is true according the the Arrhenius theory of acids?
A strong acid increases the OH-ion concentration in an aqueous solution.
A strong acid decreases the OH-ion concentration in an aqueous solution.
O A strong acid decreases the H+ and OH-ion concentration in an aqueous
solution.
A strong acid increases the H+ ion concentration in an aqueous solution.
A 5.00 g piece of metal is heated to 100.0 C then placed in a beaker containing 20.0 g of water at 10.0 C. The temperature of the water rises to 15.0 C. Calculate the specific heat of the metal
how do I do this I’m confused
by using pro.gram..
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GIVING BRAINLEST ASAP IM BEING TIMED
Two adaptations to plants are described below:
Adaptation 1: A hornwort is a nonflowering plant that produces a large number of spores instead of seeds.
Adaptation 2: A kangaroo paw has tiny, woolly hairs on it that help it hold onto water droplets.
Which statement is true about these adaptations?
Both are showing adaptations to their physical characteristics.
Both are showing adaptations to their life cycles.
Adaptation 1 is an adaptation to physical characteristics, Adaptation 2 is an adaptation to life cycle.
Adaptation 1 is an adaptation to life cycle, Adaptation 2 is an adaptation to physical characteristics.
Answer:
Adaptation 1 is an adaptation to life cycle, Adaptation 2 is an adaptation to physical characteristics.
Explanation:
Answer:
Adaptation 1: A hornwort is a nonflowering plant that produces a large number of spores instead of seeds
Hydrazine (N2H4) and dinitrogen tetroxide (N2O4) form a self-igniting mixture that has been used as a rocket propellant. The reaction products are N2 and H2O. Part A Write a balanced chemical equation for this reaction. Express your answer as a chemical equation. nothing A chemical reaction does not occur for this question. Request Answer Part B What is being oxidized, and what is being reduced
Answer:
2N₂H₄+N₂O₄→3N₂+4H₂O; N₂H₄ gets oxidized, N₂O₄ gets reduced.
Explanation:
Part AThey tell us what substances react to form what products, so we can write an unbalanced chemical equation from those substances.
N₂H₄+N₂O₄→N₂+H₂O
To balance this equation, we need to make it so there is an even amount of each element on both sides of the reaction. We can do this by multiplying the amount of each substance by adding a coefficient in front of it.
2N₂H₄+N₂O₄→3N₂+4H₂O
Part BTo identify what is being oxidized and what is being reduced, look at the oxidation charges of each element.
N₂H₄ gets oxidized, N₂O₄ gets reduced.
How many grams of solid NaOH are needed to prepare 200. mL of a 5.00% by
volume NaOH solution
A) 8
B) 10
C) 9
D) 7
Answer:
10
Explanation:
Each 100 ml should have 5 solid naom to have 5%,
For 200 ml: 200 *5%=10
The grams of Solid NaOH needed is : ( B ) 10 grams
Volume of solution = 200 mL
Percentage of solid NaOH in solution = 5.0%
Therefore the grams of solid NaOH required to prepare a 200mL solution that contains 5.0% solid will be :
5% * 200 mL
= 10 grams
Hence we can conclude that the grams of solid NaOH needed is 10 grams
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Calculate the molarity of a MgSO: solution
prepared by adding 0.37 moles of MgSO, to
enough water to make 4.9 L of solution.
Answer in umits of M.
Answer:
is
Explanation:
the explant
14. Explain, in terms of ions, why a 10.0-milliliter sample of 0.10 M NH4Cl(aq) is a poorer conductor of
electricity than a 10.0-milliliter sample of the 0.30 M NH4Cl(aq).
Neeed now
HURRY PLEASE!! Chelsea is expecting a call from her sister in New York at 1:00 p.m. Pacific time. What time will it be in New York when Chelsea's sister calls?
1:00 p.m.
9:00 a.m.
4:00 p.m.
10:00 a.m.
Answer:
it will be 4:00 pm
Explanation:
subtracting eight hours from Coordinated
Chromatin consists of long strands of material located within the nuclear membrane.
True
False
(also if u want brainlist's answer this question and ask a random question so u can give me brainlist back , deal? (i just need 2 people to answer and ill pick who gets it))
Answer:
True
Explanation:
The worst feeling is when you are hurting so badly inside but not a single tear comes out.
Anyone relate?
I know i can.
Answer:
chemistry wow
Explanation: