Answer:
The correct answer is 24.31 amu.
Explanation:
The formula for finding the average atomic mass = The sum of the percentage abundance of isotopes × the actual mass of isotopes
The average atomic mass = % abundance of Mg-24 × actual mass + % abundance of Mg-25 × its actual mass + % abundance of Mg-26 × its actual mass
Avg. Atomic mass = 0.7870 × 23.98504 + 0.1013 × 24.98584 + 0.1117 × 25.98259
Avg. atomic mass = 18.88 + 2.53 + 2.90 = 24.31 amu
The atomic mass of magnesium is 24.31 amu.
What group is calcium and sodium in?
Answer:
Calcium: Alkaline Earth
Sodium: Alkali Metal
Hope it helps!
Answer:
Calcium is in Alkaline Earth
Sodium is in Alkali Metal
What is an empirical formula?
Answer:
a formula giving the proportions of the elements present in a compound but not the actual numbers or arrangement of atoms.
Hope this helped!!!
Answer:
Empirical formulas show the simplest whole-number ratio of atoms in a compound
Explanation:
3.Identifica en tu casa 2 elementos en donde sea evidente la elasticidad y dos elementos en los que se manifieste poco y has una pequeña descripción de estos elementos y lo que le permite o no ser evidentemente elásticos
Answer:
Objetos elásticos: forma de cama y neumático de ciclo.
Objetos no elásticos: muebles y cuchara
Explicación:
Dos materiales elásticos que están presentes en las casas son forma y neumático de ciclo y dos materiales no elásticos como muebles y cuchara. Los materiales elásticos son aquellos que muestran alguna deformación en su forma al aplicar fuerza y al eliminar la fuerza, recupera su forma original, mientras que los materiales no elásticos son duros y no pueden cambiar su tamaño y forma.
Scientific method quick check
Answer:
Quick you said:
-Purpose/Question
Ask a question.
-Research
Conduct background research. Write down your sources so you can cite your references. In the modern era, a lot of your research may be conducted online. Scroll to the bottom of articles to check the references. Even if you can't access the full text of a published article, you can usually view the abstract to see the summary of other experiments. Interview experts on a topic. The more you know about a subject, the easier it will be to conduct your investigation.
-Hypothesis
Propose a hypothesis. This is a sort of educated guess about what you expect. It is a statement used to predict the outcome of an experiment. Usually, a hypothesis is written in terms of cause and effect. Alternatively, it may describe the relationship between two phenomena. One type of hypothesis is the null hypothesis or the no-difference hypothesis. This is an easy type of hypothesis to test because it assumes changing a variable will have no effect on the outcome. In reality, you probably expect a change but rejecting a hypothesis may be more useful than accepting one.
-Experiment
Design and perform an experiment to test your hypothesis. An experiment has an independent and dependent variable. You change or control the independent variable and record the effect it has on the dependent variable. It's important to change only one variable for an experiment rather than try to combine the effects of variables in an experiment. For example, if you want to test the effects of light intensity and fertilizer concentration on the growth rate of a plant, you're really looking at two separate experiments.
-Data/Analysis
Record observations and analyze the meaning of the data. Often, you'll prepare a table or graph of the data. Don't throw out data points you think are bad or that don't support your predictions. Some of the most incredible discoveries in science were made because the data looked wrong! Once you have the data, you may need to perform a mathematical analysis to support or refute your hypothesis.
-Conclusion
Conclude whether to accept or reject your hypothesis. There is no right or wrong outcome to an experiment, so either result is fine. Accepting a hypothesis does not necessarily mean it's correct! Sometimes repeating an experiment may give a different result. In other cases, a hypothesis may predict an outcome, yet you might draw an incorrect conclusion. Communicate your results. The results may be compiled into a lab report or formally submitted as a paper. Whether you accept or reject the hypothesis, you likely learned something about the subject and may wish to revise the original hypothesis or form a new one for a future experiment.
A mixture of gasoline and air explodes when it encounters a spark. This is
known as
O A. a synthesis reaction
O O O
B. a precipitation reaction
C. fuel efficiency
o
D. a combustion reaction
SUBMI
Answer:
D. A combustion reaction
Explanation:
0.10 moles of sodium sulfate is dissolved into 12 mL of solution. What is the molar concentration of the solution?
Your answer should have two significant figures (round your answer to one decimal place).
the molar concentration should be atleast 5mL off the solution since its disolved
Answer:
8.3
Explanation:
Convert mL to L.
12 mL×1 L1000 mL=0.012 L
Solve for molarity.
Molarity=moles of solute
liters of solution=0.10 mol0.012 L=8.3 M
An event planner accidentally leaves a tray of cupcakes in his car for several hours on a sunny day. When he returns, the formerly firm frosting is now runny and wet to the touch. Which answer choice best describes what happened in this scenario? The particles of frosting released energy to their surroundings and changed from the solid to the liquid state. The particles of frosting released energy to their surroundings and changed from the liquid to the solid state. The particles of frosting absorbed energy from their surroundings and changed from the solid to the liquid state. The particles of frosting absorbed energy from their surroundings and changed from the liquid to the solid state.
Answer:
The particles of frosting absorbed energy from their surroundings and changed from the solid to the liquid state.
Explanation:
On a sunny day, the energy of the particles in the surrounding is higher than the energy of the frosting tray of cupcakes.
As a result of the exchange of energy between the tray of cupcakes and the surrounding, the tray of cupcakes absorbs energy from the surrounding. When this occurs, the firm frosting is now converted from solid to liquid which is runny and wet to touch, hence the answer above.
A solution of HCL has percent by mass of 5%. What does it mean?
This means that in 100g of solution, there are 5g of HCl and 95g of water
why is carbon iv oxide used in fire extinguishers
Answer:
Carbon dioxide extinguishes work by displacing oxygen, or taking away the oxygen element of the fire triangle. The carbon dioxide is also very cold as it comes out of the extinguisher, so it cools the fuel as well.
The specific heat capacity of a pure substance can be found by dividing the heat needed to change the temperature of a sample of the substance by the mass of the sample and by the change in temperature. The specific heat capacity of a certain substance has been measured to be 3.52 J/g °C. Suppose 420.0 g of the substance is heated until the temperature of the sample has changed by 43.8 °C.
Write an equation that will let you calculate the last Q that was needed for this temperature change. Your equation should contain only symbols. Be sure to define each symbol.
Answer:
The answers to your questions are given below.
Explanation:
Data obtained from the question include:
Mass (M) = 420.0 g
Temperature change (ΔT) = 43.8 °C
Specific heat capacity (C) = 3.52 J/g °C
Heat needed (Q) =...?
The heat needed for the temperature change can be obtained by using the following formula:
Q = MCΔT
Where:
Q is the heat needed measured in joule (J).
M is the mass of substance measured in grams (g)
C is the specific heat capacity of the substance with unit J/g °C.
ΔT is the temperature change measured in degree celsius (°C).
Thus, we can calculate the heat needed to change the temperature as follow:
Q = MCΔT
Q = 420 x 3.52 x 43.8
Q = 64753.92 J
Therefore, the heat needed to cause the temperature change is 64753.92 J
A student made the Lewis dot diagram of a compound as shown. Mg is written with two dots shown on its top. Cl is written on the right side of Mg. Cl has seven dots around it. An arrow is shown from one dot on Mg toward the vacant space around Cl. Another arrow is shown from the other dot on Mg toward the vacant space around Cl. On the top, the art title is written as Students Lewis Dot Model. What is the error in the Lewis dot diagram?
Answer:
The dots were not properly located and arrows are not used in Lewis structures
Explanation:
If we intend to write a Lewis structure for a compound, that lewis structure must consist of only dots. These dots actually show the valence electrons on the outermost shell of the molecule.
We do not involve arrows when writing dot electron structures for compounds. The valence electrons of magnesium ought not to be written together because they are not a lone pair, rather they are two unpaired electrons. The use of an arrow suggests a coordinate covalent bond which is not the case here.
The correct lewis structure for MgCl2 is shown in the image attached to this answer.
Answer: B is the answer took the test
Explanation: both electrons of Mg should be transferred to one O atom...
What is indicated by 'A' in the figure below? A. -VE B. +Ea C. -Ea D. +VE
Answer:
+VE
Explanation:
If we look at the reaction profile pictured in the question, we can easily identify A as the enthalpy of the reaction. The enthalpy of reaction (ΔHrxn) is usually defined as the difference between the total enthalpy (heat content) of the products of a reaction and the total enthalpy (heat content) of the reactants in that reaction.
Looking at the figure, we can see that the enthalpy of products is greater than the enthalpy of reactants, hence ∆Hrxn is positive as stated in the answer above.
Potatoes are cut into many parts, making sure that each part has at least one eye (bud). Each piece of potato will usually grow into a new potato plant. Will a new potato plant grow, if planted only with the eye? A. Yes, a full new potato plant can grow from it. B. Yes, but the new plant will take a slightly longer time to germinate. C. No, a new potato plant will not grow because the food needed for germination comes from the potato piece. D. No, a new potato plant will not grow because the leaves emerge only from the potato piece.
Answer:
b
Explanation:
the eye is the most important so it would grow but it will take some time because if we plant it with piece it has some food
If the red car travels from 50 m to -25 m in 5 seconds, what is its velocity?
Answer:
V = 14m/s
Explanation:
velocity is the rate of change in displacement
V = (change in displacement)/time
V = (50 - (-20) )/5
V = (70)/5
V = 14m/s
what is the question tag for Lynne speaks french and German
Answer:here is it...
Explanation:
The question tag for the statement "Lynne speaks French and German" would be "doesn't she?"
The question tag is a short question added to the end of a statement to turn it into a question and seek confirmation or agreement. It is usually formed by using an auxiliary verb opposite in polarity to the main verb in the statement.
In the given statement, "Lynne speaks French and German," the main verb is "speaks." Since the main verb is in the affirmative form, the question tag should use the negative form.
Therefore, we use the auxiliary verb "doesn't" (the negative form of "does") and add the pronoun "she" to match the subject of the statement.
Know more about question tag:
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A gas has a volume of 25.0 mL at 2.50 atm. What is the volume at 457 mmHg if the temperature remains constant?
Answer:
≈ 0.104 liters
Explanation:
We can use Boyle's Law: [tex]P_{1}V_{1} = P_{2}V_{2}[/tex]
P₁ = 2.50 atm
V₁ = 25.0 mL
P₂ = 457 mmHg
V₂ = ?
Because pressure should be in atm we will convert 457 mmHg to units in atm:
1 atm = 760mmHg so we can divide 457 by 760 and we get ≈ 0.601atm
Next we can plug in the units to the equation for Boyle's Law:
(2.50)(25.0) = (0.601)(V₂)
Solve for V₂
V₂ will give you ≈ 104mL or 0.104L
Either is correct depending on which unit they are asking you to use
Use the following steps to balance the redox reaction using half-reactions. Zn(s) + Fe3+ Zn2+ + Fe(s) (unbalanced) a. Write balanced oxidation and reduction half-reactions. Indicate which is the oxidation reaction and which is the reduction reaction. (6 points) b. Balance the charge in the two half-reactions by multiplying the half-reactions by the correct multiplication factors. (4 points) c. Add the equations and simplify to get the balanced equation.
Answer:
Explanation:
a )
Zn = Zn²⁺ + 2e ( oxidation reaction )
Fe³⁺ + 3e = Fe( s ) ( reduction reaction )
b )
[ Zn = Zn²⁺ + 2e ] x 3
[ Fe³⁺ + 3e = Fe( s ) ] x 2
-------------------------------------------------------------------
3 Zn + 2 Fe³⁺ + 6e = 3 Zn²⁺ + 2 Fe ( s ) + 6e
3 Zn + 2 Fe³⁺ = 3 Zn²⁺ + 2 Fe ( s )
If a chemist wants to make one liter of a 1.5 M solution of NaOH from a stock solution of 2.5 M NaOH, how many milliliters of the stock solution would the chemist need to use?
A.6.0 x 102 mL
B. 0.60 mL
C. 1.7 x 103 mL
Answer:
0.60 mL
Explanation:
1. Set up the equation using Vi = MfVf / Mi
Vi = (1.5M · 1L) / 2.5M
2. Solve
1.5 / 2.5 = 0.6
3. Prepare a saturated solution of common salt in hot water. Suspend a thick cotton wick into this solution. Keep it undisturbed for a few days. You will find that common salt crystals will deposit on the wick. Is the change physical or chemical?
Answer:
physical
Explanation:
The change is physical.
A physical change involves a reversible change to the physical properties of substances, whereas a chemical change involves an irreversible change to the chemical properties of substances through a chemical reaction.
The dissolution of common salt is a physical change because the common salt can be retrieved by evaporating off the water. This is what was manifested by the deposition of common salt crystals on the wick.
Is wax a good conductor of electricity?
How many grams of silver will be produced if 86g of copper are used
Explain why human being is regarded as a complex machine.
Answer:
Well a human bein is a complex organism with pain and emotion.
There is a very very complex brain that recives and sends sis also faster than the eye can see.
Thats why when you touch a hot surface a lighting fast signal is sent from the hand to the brain and the brain sends a signal back to the hand to tell it what to do and this all happens a faster than a second.
A human is made out of millions, billions, trillions, and quadrillions if cells working together to perform special tasks like eating, walking, and talking.
Answer:
Humans are the only known species that are able to think as complexly as we do. For example, animals are not able to have thoughts about their thoughts. Animals are not able to ponder the existence of our universe, develop calculus, chemical solutions, etc. There are many other intelligent species- like chimpanzees and octopi. However, both of those species are limited in the type of communication, emotion, and complex thinking skills that they possess compared to human beings.
Explanation:
Balance the equation: "Sodium oxide reacts with water to form sodium hydroxide and hydrogen." I can't find the correct coefficients to balance the equation. I have written my unbalanced equation in the file attached.
Answer:
So, sodium oxide + water = sodium hydroxide + hydrogen is written Na2O+H2O-->NaOH+H.
To balance the equation it should read NaO+H2O-->2NaOH
Explanation:
Na2O+H2O-->2NaOH+0H2.......the 0H2 is dropped because there is no value
The correct balance of equation will be
Na2O + H2O - - > 2NaOH
What is a balanced chemical equation?A chemical equation where the number of atoms on both the reactant side and the product side of the reaction are equal is called a balanced chemical equation.
In a balanced chemical equation, not only the number of atoms but the charge and the mass is the same on both sides of the equation.
A chemical equation needs to be balanced to validate the law of conservation of mass. The law of conservation of mass states that the 'mass can neither be created nor destroyed in a chemical reaction'.
If the chemical equation is not balanced, it will go against the fundamental law of law of conservation of mass.
Thus, the chemical equations need to be balanced.
Therefore to balanced the given chemical equation, we equate the number of atoms on both the reactant and the product side of the reaction.
It will be written as
Na2O + H2O - - > 2NaOH
Read more about balanced chemical equations, here
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Given that the density of air is 14.4, then the vapour of sulphur IV oxide is A. 16 B. 32 C. 64 D. 128
Thank you.
Answer:
32
Explanation:
The vapour density of a gas is the number of times a given volume of gas or vapour is as heavy as the same volume of hydrogen at a particular temperature and pressure.
Vapour density = 2 × relative molecular mass of the gas or vapour
Relative molecular mass of SO2 = 32 + 2(16) = 64
Hence;
Vapour density of SO2 = 64/2
Vapour density of SO2 = 32
WILL GIVE A BRAINLIEST FOR THE ANSWER.
Pls open the picture for the question. I need the answer ASAP.
Answer:
(i) There is a very fast rate at t1, as its slope is the most significant, at t2 the rate is still positive, but it has decreased compared to t1, and at t3 the rate is almost constant, as seen by the nearly flat slope.
(ii) The trend in the reaction rate is logarithmic, with a very fast reaction rate at the beginning that slowly decreases.
Explanation:
am gonna cry plz answer Which is not an inter molecular force? Select one: a. Inter atomic bonds b. van der waals forces c. hydrogen bonds
Answer:
inter atomic bonds
Explanation:
because it is loosely held
explain why ply(ethene) can become a pollutant?
Answer:
ipotseeeeeeeeeeeeeeee
Why is particle size the main parameter used in selecting a mechanical phase-separation device?
Answer:
This is because mechanical phase-separation device such as filtration, centrifugation etc operate according to the unique particle size feature in which they are designed to separates.
The process of centrifugation separates particles of size range between 0.1 μm to 5.0 μm efficiently.
The process of filtration however varies as there are different types of pore sizes which covers a wide range of particle sizes.
calculate the amount in moles of a gas which occupies 250cm3 at s.t.p
Answer: 0.01 moles (I am guessing)
Explanation:
Firstly, cm3 and ml are equal to one another, therefore 250cm3 can also be written as 250 ml. I Googled and found that ideally, one mole of gas will occupy a volume of 22.4 L (22,400 ml) at s.t.p. 250 ml out of 22,400 ml is 0.01 rounded, therefore I assume that is the answer. About 0.01 mole occupies 250 cm3 at s.t.p.
Ethane- (-89) Butane- (0) Methanol- (64.7) Hexane- (69) Pentadecane- (270) Heptadecane- (302) a) A mixture of pendtadecane and heptadecane can be separated by______ b) Which pair of compounds are easiest to separate (i) Ethane and Pentadecane (ii) Ethane and Heptadecane (iii) Butane and Hexane (iv) Butane and Heptadecane
Answer:
(ii) Ethane and Heptadecane
Explanation:
The separation of all the species listed in the answer options for the question depends on the molar mass of each specie.
Ethane is a low molecular mass gas. It exists in the gaseous state at room temperature. However, heptadecane appears as a liquid because it has a greater relative molecular mass.
It is very easily to distinguish between the gas, ethane and the liquid heptadecane which is a high molecular mass alkane, hence the answer.
