Answer:
A Mixture of two elements
Explanation:
What is the percent by mass of sodium in Na2SO4?
Answer:
= 32.39 %
Explanation:
The relative atomic mass of sodium is 23, sulphur 32 while oxygen as a relative atomic mass of 16.
I mole of Na₂SO₄ has a relative mass of 2(23) + 32 + 4(16) = 142 grams
Of the value 142, the contribution of sodium is 2×23 =46
Thus the % composition is calculated:
46/142×100%= 32.39%
You start with 0.050 moles of ammonia in 500. mL of water. The equilibrium constant Keq is 1.8 × 10–5. What is the pH of this solution at equilibrium? Please show work!
Answer:
[tex]\boxed{11.13}[/tex]
Explanation:
The chemical equation is
[tex]\rm NH$_{3}$ + \text{H}$_{2}$O \, \rightleftharpoons \,$ NH$_{4}^{+}$ +\text{OH}$^{-}$[/tex]
For simplicity, let's rewrite this as
[tex]\rm B + H$_{2}$O \, \rightleftharpoons\,$ BH$^{+}$ + OH$^{-}$[/tex]
1. Initial concentration of NH₃
[tex]\text{[B]} = \dfrac{\text{moles}}{\text{litres}} = \dfrac{\text{0.050 mol}}{\text{0.500 L}} = \text{0.100 mol/L}[/tex]
2. Calculate [OH]⁻
We can use an ICE table to do the calculation.
B + H₂O ⇌ BH⁺ + OH⁻
I/mol·L⁻¹: 0.100 0 0
C/mol·L⁻¹: -x +x +x
E/mol·L⁻¹: 0.100 - x x x
[tex]K_{\text{b}} = \dfrac{\text{[BH}^{+}]\text{[OH}^{-}]}{\text{[B]}} = 1.8 \times 10^{-5}\\\\\dfrac{x^{2}}{0.100 - x} = 1.8 \times 10^{-5}[/tex]
Check for negligibility:
\[tex]\dfrac{0.100 }{1.8 \times 10^{-5}} = 5600 > 400\\\\ x \ll 0.100[/tex]
3. Solve for x
[tex]\dfrac{x^{2}}{0.100} = 1.8 \times 10^{-5}\\\\x^{2} = 0.100 \times 1.8 \times 10^{-5}\\\\x^{2} = 1.80 \times 10^{-6}\\\\x = \sqrt{1.80 \times 10^{-6}}\\\\x = \text{[OH]}^{-} = 1.34 \times 10^{-3} \text{ mol/L}[/tex]
4. Calculate the pH
[tex]\text{pOH} = -\log \text{[OH}^{-}] = -\log(1.34 \times 10^{-3}) = 2.87\\\\\text{pH} = 14.00 - \text{pOH} = 14.00 - 2.87 = \mathbf{11.13}\\\\\text{The pH of the solution at equilibrium is } \boxed{\mathbf{11.13}}[/tex]
0.0006510 kg has
how many significant figures.
Answer:
4 significant figures as zeros after decimal should not be counted
Explanation:
Please mark brainliest and have a great day!
Answer:
4 significant figures
How are nuclear reactions different from chemical reactions?
Select all that apply.
In nuclear reactions, the identities of the elements change.
In nuclear reactions, the identities of the elements stay the same.
In nuclear reactions, the reactions happen at a set rate.
In nuclear reactions, the reactions happen at a varied rate.
Explanation:
Nuclear reactions are defined as the reaction in which there occurs change in the nucleus of an atom due to change in number of protons or neutrons of an atom.
For example, [tex]^{2}_{1}H + ^{2}_{1} \rightarrow ^{4}_{2}He[/tex] is a nuclear reaction.
Hence, identity of the element changes in a nuclear reaction. Also, nuclear reaction can occur at varied rates as they are not affected by temperature, pressure or catalyst.
Whereas a chemical reaction is defined as the reaction where there occurs exchange of electrons between the combining atoms.
For example, [tex]2Na(s) + Cl_{2}(g) \rightarrow 2NaCl[/tex] is a chemical change.
Thus, we can conclude that nuclear reactions are different from chemical reactions as follows.
In nuclear reactions, the identities of the elements change.In nuclear reactions, the reactions happen at a varied rate.Which of the following groups gets energy directly from the grass it eats?
A.producers
B. Decomposers
C.primary consumer
D.secondary consumers
Answer: C. Primary Consumers
Explanation:
Answer:
Primary consumer.
Explanation:
Food chain may be defined as the sequential flow of food energy from one level to the next tropic level. Producers are the first organism that occupies the first tropic level in the food chain.
Producers prepare their food by themselves. Primary consumers get their food by eating directly the producers. Primary consumers are generally feed on the plants and grass.
Thus, the correct answer is option (C).
BRAINIEST AND MAX POINTS
The diagram below shows four processes, A, B, C, and D, by which carbon circulates between the atmosphere, plants, and animals.
Which processes represent respiration?
Process A and Process C
Process B and Process D
Process A and Process D
Process B and Process C
Answer:
precess a and b
Explanation:
Answer: I believe the answer is A) Process A and Process C !!!!!!!!
WILL MARK BRAINLIEST ASAP 20 POINTS
Answer:
elta H = Potential Energy of the Products - Potential Energy of the Reactants.
This would be C-A = delta H
The activation energy would be B-A
This is the energy necessary to start the reaction
Answer:
its the relationship between energies and the coeficcients on the graph.
Explanation:
Complete the statements based on water’s polarity and ability to form hydrogen bonds. Water’s boiling point is abnormally than expected. Water has a surface tension, allowing adhesion, cohesion, and capillary action. Water has a capacity to retain heat, keeping moderate climates warmer in the winter. Water as it freezes, so ice floats when expected to sink.
answers are higher high high expands
Answer:
1 Higher
2 High
3 High
4 Expands
Explanation:
Answer:
a) Water's boiling point is abnormally higher than expected
b) Water has a high surface tension allowing adhesion, cohesion and capillary action.
c) Water has a high capacity to retain heat, keeping moderate climates warmer in the winter.
d) Water expands as it freezes, so ice floats when expected to sink.
Explanation:
a) Because of its small molecular weight, it's expected that the water has a low boiling point, but the abillity to make hydrogen bonds generates an atraction force between the molecules much more stronger that expected.
This phenomenom implies that the water has higher boiling point than other heavier compounds.
b) The high surface tension its the result of the hydrogen bonds and the polarity of the water molecules, giving the water molecules stronger bonds and like a very strong net, makes it harder to get through.
This is the cause of the listed phenomena: cohesion, adhesion and capillary action.
c) Another effect of the hydrogen bonds of the water is its high thermal capacity.
The hydrogen bonds are the strongest of the molecular bonds (H bonds, dipole-dipole and London) and the stronger the bond is, the higher the amount of energy (in this case heat) it can absorb before its rupture.
This is why water have a high thermal capacity compared with other molecules that only have London or dipole bonds.
d) Water expands when it freezes because the molecules rearrange and during that, many of the hydrogen bonds break.
When that happens, the water molecules have a weaker attraction than before and in consecuence the water (ice) expands.
Also, ice floats beacuse once it expands it has a lower density compared to the water.
A group of students working in a high school chemistry lab believe they have discovered a new element! How exciting? Upon further testing by scientists (with better equipment), it is found that the new element contains 74 protons and 110 neutrons.
What is the atomic number?
What is the mass number?
Is this a new element? Explain.
Give the name and symbol for this element.
Is it solid, liquid, or gas? Explain
Answer:
Explanation:
Information given about the element:
Number of protons = 74
Number of neutrons = 110
For the atomic number:
Neutral atoms such as this one would have their atomic number to be the same with their number of electrons and protons:
atomic number = number of protons = number of electrons
The atomic number would therefore be 74
For the mass number:
The mass of an atom is centrally concentrated within the tiny nucleus. The mass number is the sum of protons and neutrons in an atom. Protons and neutrons are nuclear particles and are called nucleons:
Mass number = number of protons + number of neutrons = 74+110=184
Is this a new element?
From the peroidic table, tungsten(W) perfectly fits this description of the atom. It has an atomic number of 74 and a mass number of approximately 184. The element is not a new element.
Is it solid, liquid, or gas?
The element is a hard metallic solid. It is a classified as a transition metal on the periodic table. Transition metals have very unique metals and are mostly solids.
Answer:
1) The atomic number of this element is 74, because number of protons = atomic number
2) Mass number of this element is 184
Ar=Z+N=74+110=184
3) It isn't a new element. An element with such atomic and mass numbers exists
4) It is Wolfram. Symbol: W
5) Solid
Sorry if I made mistakes. I started learning English recently
select all that apply.. which of these elements from the d-block have electron configurations that don't fit the expected pattern? ruthenium,technetium,good,silver
Answer:
These are the ten elements other than chromium and copper in the d-block don’t fit the expected configuration pattern:
niobium (Nb)
molybdenum (Mo)
ruthenium (Ru)
rhodium (Rh)
palladium (Pd)
silver (Ag)
platinum (Pt)
gold (Au)
darmstadtium (Ds)
roentgenium (Rg)
Explanation:
Answer:
ruthenium (Ru)
gold (Au)
silver (Ag)
Explanation:
Elements that form ionic bonds generally have how many valence electrons? ± 1 or ± 2 ± 2 or ± 3 ± 4 ± 5
Answer:
± 1 or ± 2
Explanation:
Electrovalent bonds are chemical bonds that are established on the premise of transferring electrons between two atoms.
In this bond type, a higly electronegative atom, typically a non-metal receives electrons from an atom with lesser electronegativity, a metal.
To know the number of electrons involved in forming electrovalent bonds, we typically look at the groups of atoms that combines to form the bond.
Metals are found in group I and II on the periodic table. Metals are electropositive and are good electron donors. These metals have 1 and 2 electrons in their valence shell respectively. In like manners, the more electronegative atoms are found in group VI and VII. The elements in these groups are non-metals with high electronegativity and requires just 1 and 2 electrons to complete their octet.
Answer:
± 1 or ± 2
Explanation:
which class of compunds has the general formula r-o-r
Answer:
R-O-R is the general formula for Symmetrical Ethers,in which both alkyl groups attached on oxygen are same .
Explanation:
Please mark brainliest and have a great day!
HELP NEED HELP PLEASE !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Answer: B) 4.2 M
Explanation:
Molarity = moles of solute/litre of solution
1560mL/1000 = 1.56 litres
6.5/1.56 = x/1
x = 4.2
M of solution = 4.2
QUICK PLEASE HELP!!!during a combustion reaction, 5.00 grams of oxygen reacted with 5.00 grams of CH4.
What is the amount of the leftover reactant?
4.00 grams of methane
3.75 grams of methane
2.75 grams of oxygen
1.75 grams of oxygen
To determine the leftover reactant in the combustion of 5.00 grams of oxygen and 5.00 grams of CH4, the limiting reagent calculation shows that the leftover reactant is 3.75 grams of methane as oxygen is the limiting reagent.
Explanation:To determine the amount of the leftover reactant in a combustion reaction involving 5.00 grams of oxygen and 5.00 grams of CH4, we need to conduct a limiting reagent calculation. The balanced chemical equation for the combustion of methane (CH4) is:
CH4(g) + 2O2(g) → CO2(g) + 2H2O(l)
From the balanced equation, we can see that one mole of CH4 reacts with two moles of O2. The molar mass of CH4 is 16.04 g/mol, and the molar mass of O2 is 32.00 g/mol, so we can use these to convert the mass of each reactant to moles:
For 5.00 g of CH4: 5.00 g / 16.04 g/mol = 0.3117 mol CH4For 5.00 g of O2: 5.00 g / 32.00 g/mol = 0.15625 mol O2Since the reaction requires 2 moles of O2 for each mole of CH4, we can calculate the needed moles of O2 for the reaction with the available CH4:
0.3117 mol CH4 × 2 mol O2 / 1 mol CH4 = 0.6234 mol O2 needed
However, we only have 0.15625 mol of O2 available, which is less than 0.6234 mol. This means O2 is the limiting reagent, and there will be some unreacted CH4 left over. Since all of the oxygen will be used up, we can calculate the leftover mass of methane:
0.15625 mol O2 × 1 mol CH4 / 2 mol O2 = 0.078125 mol CH4 reacted
0.3117 mol CH4 - 0.078125 mol CH4 reacted = 0.233575 mol CH4 unreacted
Finally, we convert the moles of unreacted CH4 back to grams:
0.233575 mol CH4 × 16.04 g/mol = 3.75 grams of CH4
Therefore, the amount of the leftover reactant is 3.75 grams of methane.
PLEASE HELP!!!
WILL GIVE BRAINLIEST!!!!
Is this a strong positive linear association or something else?
Answer:
Yes; the graph shows a strong positive linear association.
Explanation:
Majority of the points outline a line of the graph. There are only a few outliers.
Given pH = 6.75,
Is this acidic, basic or neutral?
How do you know?
Answer:
Acidic.
Explanation:
pH is a logarithmic function of [H+]:
pH = −log[H+]
pH is usually (but not always) between 0 and 14. Knowing the dependence of pH on [H+], we can summarize as follows:
If pH < 7, then the solution is acidic.
If pH = 7, then the solution is neutral.
If pH > 7, then the solution is basic.
Given pH is 6.75 so it is acidic.
molar mass of fe2o3 g/mol
Answer:
159.7
Explanation:
hope this helps
How do limiting factors most affect population size?
O
stop population growth
restrict population growth
increase population size
result in positive impacts
O
Answer:
restrict population growth ( second choice).
what is the wavelength of a 3*10^12 Hz infrared wave
A 3*10^20m
B 1* 10^4m
C 3*10^-3m
D 1*10^-4 m
Answer:
D. 1 × 10⁻⁴ m
Explanation:
Electromagnetic waves travel through space with the speed of light which is approximately 3.0 ×10⁻⁸ m/s.
The speed is calculated as follows:
c=λf
Where λ is the wavelength of the wave, f the frequency and c the speed of light.
Thus λ=c/f
=(3×10⁸ m/s) / (3×10¹²Hz)
Wavelength, λ= 1 × 10⁻⁴ m
Answer:
D
Explanation:
A.P.E.X.
pls help!!
Explain the resonance structures for the nitrate ion, NO3−.
Answer:
Resonance structures for the nitrate ion exist because there are more than one Lewis Structures for this ion.
Explanation:
How many bonds in each nitrate ion?
To answer this question, start by considering how many electrons each atom need for an octet.
Each N atom needs three electrons to achieve an octet.Each O atom need two electrons to achieve an octet.The three O atoms and one N atom in each nitrate ion will need [tex]3\times 2 + 3 = 9[/tex] electrons in total to be stable. However, the ion carries a charge of [tex]-1[/tex]. In other words, atoms in the ion have already acquired one extra electron. Now they need only [tex]9 - 1 = 8[/tex] electrons.
Atoms share electrons by forming bonds. In effect, each chemical bond (a pair of shared electrons) adds two electrons to the bonding atoms. Atoms in the nitrate ion will form [tex]8/2 = 4[/tex] chemical bonds.
However, there are only three bonding position available. One of the three positions will see a double bond while each of the other two will see a single bond. However, the double bond can be at any of the three bonding position. There are thus three possible Lewis Structures. See the sketched. Note that the three structures are interconvertible by moving only the electrons but not any atoms. Hence the name resonance structures.
Keep in mind that in reality, the pi electrons from the double bond are delocalized across all three possible bonding positions. All three N-O bonds are of equal length.
Why does a red shoe appear red in daylight
Answer:
Because it does
Explanation:from sun light DUHHHH
According to Boyle's law, what would happen to the temperature of a gas if the pressure were halved as the number of moles and the volume were held constant?
A.The temperature would double.
B.The temperature would be reduced by half.
C.The temperature would quadruple.
D.The temperature would be one-quarter of its original value.
According to Boyle's law, the temperature would double of a gas if the pressure were halved as the number of moles and the volume were held constant. Hence, option A is correct.
What is Boyle's law?Boyle's law states that at constant temperature, the pressure exerted by a gas is inversely proportional to the volume occupied by it.
If temperature is held constant, the equation is reduced to Boyle's law. Therefore, if you decrease the pressure (P↓) of a fixed amount of gas, its volume (v ↑) will increase.
(P↓) → (v ↑)
P∝ [tex]\frac{1}{V}[/tex]
However, if you were to maintain a constant volume while decreasing pressure, the temperature would also have to decrease.
Thus, according to Boyle's law, the temperature would double of a gas if the pressure were halved as the number of moles and the volume were held constant.
Hence, option A is correct.
Learn more about the Boyle's law here:
https://brainly.com/question/24345272
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A salad including lettuce, tomatoes, and onions would be classified as a _________.
Answer:
simple salad
Explanation:
Hi.
Anwers : Vegetable salad.
Achievements.
The first step of the water cycle is that water _______________ into the air.
Answer:
evaporates
Explanation:
the heat from the sun causes it to evaporate
How many grams of aluminum are in 0.58 moles of Al2O3.2H:0?
Answer:
80.04 gram
Explanation:
mass = moles × relative formula mass
= 0.58×138
= 80.04
Homologous chromosomes pair up during what phase of meiosis:
Answer:
prophase I
Explanation:
Homologous chromosomes pair up during prophase I of meiosis.
A potential energy diagram is shown.
What is the activation energy of this reaction?
Answer:
Ea = 35 kJ.
Explanation:
Activation energy (Ea) is the difference between the potential energy of intermediate "activated complex/ peak" and reactants.
Ea = P.E. of products - P.E. of reactants = 65 kJ - 30 kJ = 35 kJ.
kindly find the attached image.
Which of the following is a sign a chemical reaction has occurred?
Answer:
2. A piece of metal is placed in water and produces sparks and gas
Explanation:
The production of gas is usually a sign of a chemical reaction. The metal is reacting with the water to form a new substance (the gas).
Incorrect answers and why:
1. Changing colors can be a sign of a chemical reaction, but in this case it's more likely that the colors blended together. (If it was something like two clear liquids combining to form a yellow liquid, then it would be more clear evidence of a chemical reaction)
3. The liquid is boiling
4. The powder dissolved into the liquid
I hope this helps!
The statement that is a sign a chemical reaction has occurred is a piece of metal is placed in water and produces sparks and gas. The correct option is b.
What is a chemical reaction?A chemical reaction is a process in which two or more substances called reactants react to form a different substance or compound, called a product. The metal reacts with water and forms gas and sparks in a chemical reaction.
Although a chemical reaction might cause colors to change, in this case, it's more likely that the hues just mixed. (If it involved the blending of two clear liquids to create a yellow liquid, that would be more convincing proof of a chemical reaction.)
Thus, the correct option is b. A piece of metal is placed in water and produces sparks and gas.
To learn more about a chemical reaction, refer to the below link:
https://brainly.com/question/3461108
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The following chemical equation is not balanced.
Ca + AIPO4 — Al + Caz(PO4)2
When the equation is balanced, what is the coefficient for pure aluminum
(AI)?
A) 1
B) 2
C) 4
D 8
Answer:
3Ca + 2AlPO4 = Ca3(PO4)2 + 2Al.
That is B
Answer:
The stoichiometric coefficient of aluminium is 2 that is option B is correct.
Explanation:
Stoichiometric coefficient is the numeral coming or written before the symbol of compound or an element in balanced chemical reaction equation.
[tex]3Ca + 2AIPO_4 \rightarrow 2Al + Ca_3(PO_4)_2[/tex]
According to stoichiometry, 3 moles of calcium reacts with 2 moles of aluminum phosphate to give 2 moles of aluminium and 1 mole of calcium phosphate.
The stoichiometric coefficient of calcium is = 3
The stoichiometric coefficient of aluminum phosphate = 3
The stoichiometric coefficient of aluminium = 2
The stoichiometric coefficient of calcium phosphate = 1
what does the capital letter, such as T, represent in a punnett square
Answer: A dominant gene.
Explanation:
Answer:
The dominant form of a gene
Explanation:
The capital letter, such as T, represents the dominant form of a gene in a punnett square.