The type of mixture if they were having spaghetti and meatballs for dinner is
a heterogeneous mixture.
Heterogeneous mixture involves two or more substances not having a
uniform composition in the mixture. The substances in the mixture are
usually differentiated easily.
In the case of the spaghetti and meatballs , there is no uniform composition
and they are easily differentiated which means that the mixture is a
heterogeneous mixture.
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The half life for uranium-235 is 7.0x10 8years. a. How many half-lives did the sample go through at the end of 2.8x10 9years? b. How much of a 0.74mg sample of uranium-235 will remain after 2.8x10 9years?
Answer:
A 4 half-life
B. 0.05 mg
Explanation:
A. Determination of the number of half-lives after 2.8×10⁹ years.
From the question given above,
7×10⁸ years = 1 half life
Therefore
2.8×10⁹ years = 2.8×10⁹ years × 1 half life / 7×10⁸ years
2.8×10⁹ years = 4 half life
Thus, the sample went through 4 half-lives at the end of 2.8×10⁹ years.
B. Determination of the amount of the sample remaining after 2.8×10⁹ years.
Original amount (N₀) = 0.74 mg
half life (t½) = 7×10⁸ years
Time (t) = 2.8×10⁹ years
Amount remaining (N) =?
Next, we shall determine the rate of disintegration. This can be obtained as follow:
half life (t½) = 7×10⁸ years
Decay constant (K) =?
K = 0.693 / t½
K = 0.693 / 7×10⁸
K = 9.9×10¯¹⁰ /year
Finally, we shall determine the amount remaining as follow:
Original amount (N₀) = 0.74 mg
Time (t) = 2.8×10⁹ years
Decay constant (K) = 9.9×10¯¹⁰ /year
Amount remaining (N) =?
Log (N₀/N) = kt / 2.303
Log (0.74/N) = 9.9×10¯¹⁰×2.8×10⁹ /2.303
Log (0.74/N) = 2.772 / 2.303
Log (0.74/N) = 1.2036
Take the antilog of 1.2036
0.74/N = antilog (1.2036)
0.74 / N = 15.98
Cross multiply
0.74 = N × 15.98
Divide both side by 15.98
N = 0.74 / 15.98
N = 0.05 mg
Thus, 0.05 mg of the sample will remain after 2.8×10⁹ years
The amount of uranium sample remained after 4 cycles in [tex]\rm 2.8\;\times\;10^9[/tex] years has been 0.04625 mg.
The half-life can be described as the time required by the element to reduce to its half concentration from the initial concentration.
A. The number of half-life cycles can be calculated as:
[tex]\rm 7.0\;\times\;10^8[/tex] = 1 cycle
[tex]\rm 2.8\;\times\;10^9[/tex] = [tex]\rm \dfrac{1}{\rm 7.0\;\times\;10^8}\;\times\;2.8\;\times\;10^9[/tex]
= 4 cycles.
The number of half-life cycles after [tex]\rm 2.8\;\times\;10^9[/tex] years are 4 cycles.
B. The amount of sample remained can be calculated as:
Sample remained = Initial sample [tex]\rm \times\;\dfrac{1}{2}^\frac{time}{Half-life}[/tex]
Sample remained = 0.74 mg [tex]\rm \times\;\dfrac{1}{2}^\frac{2.8\;\times\;10^9}{7.0\;\times\;10^8}[/tex]
Smaple remianed = 0.74 [tex]\rm \times\;\dfrac{1}{2}^4[/tex]
Sample remained = 0.74 [tex]\times[/tex] 0.0625 mg
Sample remained = 0.04625 mg.
The amount of uranium sample remained after 4 cycles in [tex]\rm 2.8\;\times\;10^9[/tex] years has been 0.04625 mg.
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What element do you think would easily react with Calcium? Why?
Is it a model answer key
Answer:
is what a model answer key
I am going to go with yes. Imao
pls pls answer questions for chem final within 45 mins i will give brainliest
which of the following elements is a metalloid
Traditionally they include boron from group 3A, silicon and germanium in group 4A, aresnic and antimony in group 5A and tellurium from group 6A, although sometimes selenium, astatine, polonium and even bismuth have also been considered as metalloids. Typically metalloids are brittle and show a semi-metallic luster.
The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Five elements are less frequently so classified: carbon, aluminium, selenium, polonium, and astatine.
Which balanced equation BEST describes this reaction?
Answer:
Explanation:
It is 1.
Answer:
2Al + 5 Br2-----> 2AlBr3 + 2Br2
Explanation:
Is it easier to remove on electron from a sodium (Na) or aluminum (Al) atom? From Na+ or Al+? From Na2+ or Al2+?
Answer: It's easier for sodium to lose an electron because it has one valence electron whereas aluminum three valence electrons. It's easier for sodium in the other two examples as well because of the valance electrons and because it is very reactive with most elements because it really wants to get rid of the extra electron n the valance shell.
An example of matter made up of only one type of element is
Answer:
Carbon, in all its states of matter.
Explanation:
Arrange the following elements (E, K, P, B) according to increasing atomic radius
Answer:
B
P
K
Explanation:
K: 203pm
B: 84pm
P: 107pm
There isn't an E on the Periodic Table?!
Which drawing is a structural model of C3Hg?
Answer:
The correct option is C
Explanation:
The structural model of C₃H₈ is that of option C.
In Structural model which can also be known as structural formula, the atoms of a molecule or compound are identified by the location of chemical bonds that exists between them. A structural formula is seen to consist of symbols. In this case, the atoms are connected by short lines. These short lines actually represent their chemical bonds. Where one, two, or three lines that connect each element that make up the compound stands for single, double, or triple bonds, respectively.
Answer:
C
Explanation:
An example of a physical change is
A) crushing a rock
B) shirt fading in the sun
(From USATESTPREP)
Answer:
A: Crushing a Rock
Explanation:
The rock is physicially being broken down and turned into either smaller pieces of rock or dust if you pound it hard enough.
Answer:
the answer is a) crushing a rock because even though you broke it, its still a rock just in smaller pieces. B is not the answer because its a chemical change. The shirt is losing colour and you can't reverse it.
In ionic bonding, atoms _____.
share electrons
are connected by strong electrical forces
lose protons and form ions
stop moving completely
Answer:
lose protons and form ions
Explanation:
I thjink hope this helps
PLease mark brainliest
who organized elements according to increasing atomic mass
Answer:
Mendeleev
Explanation:
How many moles of calcium are in 425 grams?
Answer:
10.6
Explanation:
10,604 in other words not in a decimal
There are 10.6 moles of calcium in 425 g of calcium.
Given to us is the mass of calcium which is 425 g, we also know the molar mass of the calcium which is 40.08 g/mol
To calculate the number of moles in a given mass of a substance, you need to divide the mass by the molar mass of the substance.
Using this information, we can calculate the number of moles of calcium in 425 grams:
Number of moles = Mass (g) / Molar mass (g/mol)
Number of moles = 425 g / 40.08 g/mol
Number of moles ≈ 10.61 mol
Therefore, there are approximately 10.61 moles of calcium in 425 grams.
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#SPJ 2
What are the spectator ions in the equation below? Select all that apply.
Pb(NO3)2(aq) + H2SO4(aq) → PbSO4(s) + 2 HNO3(aq)
Answer:
H+ and NO3- ions
Explanation:
The Pb²+ ions react with the SO4²‐ ions to form a solid precipitate, i.e. they bond together and undergo a phase change;
On the contrary, the H+ and NO3- ions are aqueous ions before the reaction and the same after the reaction, i.e. they don't change;
Hence, the H+ and NO3- ions are spectator ions
The way to do this type of question is to consider what changes and what doesn't, look at phase changes and oxidation state changes
Margie used arrows to represent the gases that enter and leave a plant during the process of photosynthesis, as shown below.
Answer:
the last one
Explanation:
Answer:
D
Explanation:
Please help. I'll give brainliest :)
Which answer describes a type of chemical weathering?
A. ice freezing in rock crevices
B. tafoni from salt crystallization
C. water changes rock crystals into hydrates
D. moving water over rock
Answer:
The answer is c, i just got it right on my test
Explanation:
stay safe!
What is the outcome of all chemical changes when two substances are combined?
A. A new substance forms with identical properties.
B. The two substances release an odor.
C. The two substances change color.
D. A new substance forms with different properties.
Answer:
D
Explanation:
Because when you combine chemical substances they create a new substance unlike physical substances .
Answer:
D- A new substance forms with different properties
Explanation:
When a chemical change occurs, it causes the matter to form into a completely new substance. Because of this, the new substance will have different properties than the original substance. Options B and C are true for some chemical changes, but not all changes. Option A is incorrect because the substance has different properties than the original substance. Thus, Option D is correct.
- I took the quiz and got 100%
Hope this helps!
A student made copper sulfate using 0.250 moles of copper oxide and 0.500 moles of sulfuric acid.
Calculate the maximum mass of copper sulfate which could be produced.
Give your answer to 3 significant figures.
Relative formula mass (Mr) CuSO4 = 159.5 *
Answer:
39.9g is the maximum mass of copper sulfate which could be produced
Explanation:
1 mole of Copper oxide, CuO contains 1 mole of Cu
In the same way, 1 mole of sulfuric acid, H₂SO₄, contains 1 mole of sulfate ion, SO₄²⁻.
Thus we can understand that there are 0.250moles of Cu and 0.500 moles of SO₄²⁻ to produce CuSO₄.
The maximum moles that could be produced are 0.250 moles (Copper is limiting reactant).
To convert these moles to mass we use the relative formula mass:
0.250 moles CuSO₄ * (159.5g/mol) =
39.9g is the maximum mass of copper sulfate which could be producedCan some please help me fast!!?
Answer:
Last one
Explanation:
How can you increasethe concentration of a solution of a solid in water?a. By dividing the solution between two containersb. By evaporating some of the waterc. By adding water and Stirringd. By vigorously stirring alone
Answer:
By adding water stirring
Explanation:
PLZ HELP, NO MESSING AROUND, WILL GIVE BRAINLIEST!
Covalent bond is a type of chemical bond which is due to the sharing an electron from each and every atom that is participating in the bond.
Ionic Bond:Ionic bond is a type of bond which is formed due to the complete donation of an electron from one atom to another.
Ionic bond is formed between metals and non-metals. The group which provide the Metal are IA and IIA i.e. S block elements. The group which mostly provide non-metal is VII A i.e. halogens. The Metals give up their ONLY Valance shell electron which is accepted by the Non-metal. This results in formation of ions, The Metals gets the positive charge thus called cation and The non-metal gets a negative charge thus called anion. These Positive and Negative ion attract each other resulting in the formation of IONIC BOND.
_____________________________________The Ionic bond is formed between The metal and non metal because, the metals have low ionization energy due to which the valence shell is ejected out easily, and The Non-Metals have high electron affinity which means that they attract an electron with greater force because they need one electron to complete their octet. As the non metal has high electron affinity and metal have low electron affinity thus the electronegativity difference between the non metal and metal is more than 2 thus they make ionic bond.
_____________________________________Rule of Electronegativity:Electronegativity is the tendency of an atom to attract shared pair of electron. If there is electronegativity difference between the two atom more than 2 then it makes IONIC BOND. If the electronegativity difference is less than 2, it makes COVALENT BOND.
_____________________________________Question:The question says, the KCl has ionic bond but HCl has covalent bond, why?
Answer:Answer is that KCl has electronegativity difference between K and Cl atom more than 2 thus it forms ionic bond. H and Cl has electronegativity difference of less than 2 thus it makes Covalent Bond. K donates its valence electron completely to the Chlorine atom because chlorine has much more electronegativity than potassium(K). H shares an electron with chlorine, it is not completely donated. H has pair of electron for sometime and chlorine has pair of electron for sometime, It is because the Chlorine and Hydrogen has less difference of electronegativity so they attract with almost same electronegativity.
_____________________________________Best Regards,'Borz'How are particle movement and heat related?
Write three sentences that provide evidence supporting your claim about how the illustration and student observations support the cell theory?
Answer:
The cell theory claims these three components:
1. cell is the smallest functional unit of life: It can be observed under the microscope that cells have various type of molecules and organelles present and have adifferent functional role in the cell which explains that the cell is the smallest unit of life as its molecules or organelles can not carry the life process on their own.
2. All organisms are made up of cells: From bacteria and archaea to human and other life forms are made up of a single cell or organization of cells in a specific pattern it also can be observed by the microscopic of blood or other tissue or cell of an organism.
3. Arise from pre-existing cell: The cells are can be studied under a microscope during cell division where we can observe that new cells come from the pre existing cell by the cell division.
Homework: Earth's Outer Layer
You have been investigating the question What is the land like underneath Earth's surface?
Use the map below to show your thinking about this question. Show where Earth's outer layer is
made of hard, solid rock by shading those regions.
Answer:
It goes the crust mantle outer core and inner core. The crust is what we are standing on it has dirt, rock, stone, the mantle it has lots of silicate rocks and magnesium. The outer core has liquid nickel and iron and the inner core has solid metals
Mantle and core layers are present underneath Earth's surface.
The land underneath Earth's surface has mantle, outer core and inner core. The surface of the earth is the crust which is solid and hard. This surface of earth becomes hard due to cooling of the surface with the help of environmental conditions.
Mantle layer of earth has high temperature than crust whereas the inner and outer core is more hotter than mantle where all the materials are present in liquid state so we can say that inside the earth mantle and core layers are present.
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Teresa has a $100 gift card to her favorite restaurant. Each day, she uses her gift card to buy the same lunch for $8.50. Colin has a $75 gift card to the same restaurant. His lunches cost $6 each. For what numbers of lunches will Teresa's gift card balance be greater than Colin's gift card balance?
Answer:
No
Explanation:
If Teresa has a $100 Gift Card and her lunch is $8.50 everyday, $8.50 x 10 = 10 Lunchs for a total of $85 then add one more which = 11 Lunchs for a total of 93.50, this means she can not buy another lunch, Colin has a $75 gift card and his lunch is $6 everyday, so $6 x 10 = $60 for a total of 10 lunchs plus add 2 which is 12 lunchs for a total of $72 which means No Teresa's Gift Card Will Not Be Greater In Lunchs.
The default solution is water, describe the solution. What is the pH?
Benzene has been used as a solvent for waxes and oils. In 1981 the EPA listed benzene as a carcinogen. What is the molecular formula of benzene if the empirical formula is C1H1, and the approximate molar mass is 78 g/mol
Answer:
C₆H₆
Explanation:
From the question given above, the following data were obtained:
Empirical formula = CH
Molar mass of compound = 78 g/mol
Molecular formula =?
The formula of the compound can be obtained as follow:
Molecular formula = n × Empirical formula
Molecular formula = ₙ[CH]
n[CH] = 78
n[12 + 2] = 78
14n = 78
Divide both side by side 14
n = 78/14
n = 6
Molecular formula = ₙ[CH]
Molecular formula = ₆[CH]
Molecular formula = C₆H₆
Thus, the molecular formula of the compound is C₆H₆
Which of the following is an oxidation-reduction reaction?
Answer:
last choice
Explanation:
oxidation and reduction can be defined in terms of adding or removing oxygen to a compound
oxidation is gaining oxygen
reduction is to loss oxygen
Explain how the rock cycle works.
Be sure to include the name of each type of rock in your description.
(Igneous rock, metamorphic rock, and sedimentary rocks)
