which expression has a value of 10
A. (10+10)/5-3
B. (10+10)/(5-3)
C. (10+10/5)-3
D. 10+10/(5-3)
(math)

Hope my answer helps you.

464 g radioisotope was present when the sample was put in storage

Given

Sample waste of Co-60 = 14.5 g

26.5 years in storage

Required

Initial sample

Solution

General formulas used in decay:  

[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]

t = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time  

Half-life of Co-60 = 5.3 years

Input the value :

[tex]\tt 14.5=No.\dfrac{1}{2}^{26.5/5.3}\\\\14.5=No.\dfrac{1}{2}^5\\\\No=\boxed{\bold{464~g}}[/tex]

Answer:

1813.74g

Explanation:

Given parameters:

Number of moles of radon  = 8.17moles

Unknown:

Mass of radon  = ?

Solution:

To solve this problem, we use the expression below:

      Number of moles = [tex]\frac{mass}{molar mass}[/tex]  

Molar mass of radon  = 222g/mol

Now insert the parameters and solve;

    Mass of radon  = Number of moles x molar mass

                              = 8.17 x 222

                              = 1813.74g

Moles of Ammonia (NH₃) in solution = 1.14

Given

0.175 L of 6.50 M aqueous ammonia

Required

moles of ammonia

Solution

Ammonia = NH₃

Molarity = moles of solute per liter of solution

[tex]\tt M=\dfrac{n}{V}[/tex]

n = M x V

n = 6.50 M x 0.175 L

n = 1.1375 moles

In a multiplication operation: the significant digits in the final product must follow the number of significant digits that are at least in the numbers involved in multiplying

6.50 = 3 sig fig

0.175 = 3 sig fig

So the result must be 3 sig fig

1.1375 rounded to 1.14

Answer A. The electronegativity of one atom is less than 1.7

Answer: its C

Explanation: i just got it wrong the right answer is c

Answer:

About 140 gallons?

Explanation:

Answer:

When moving from left to the right of a period, the number of electrons increases and the strength of shielding increases. As you move across period the number of shells remain same, the shielding effect will also remain constant.

Explanation:

Answer: I beleive it is the volumetric flask.

Explanation:

I searched it up.

Answer:

Magnesium, calcium and sodium.

Explanation:

Magnesium, calcium, sodium, and other beneficial minerals are the substances present in drinking water. Different regions have different fluoride concentration in their water such as in sea water, fluoride level is 1.1 mg/L while in surface water, the concentration is 0.01–0.3 ppm. Yes, fluoride is soluble in water. No, fluoride should not be added to drinking water because it harm for health. All the questions can be answered by science because it is related to chemistry.

Explanation:

The neutral aluminium atom loses all 3 of its valence electrons to obtain a stable octet structure.

The aluminium ion has a positive charge of 3.

=> Al3+, Charge = +3.

Answer:

solid liquid gas

Explanation:

solid liquid gas

Answer:

It would be false because there are series circuit that only has one path

Answer:

lithosphere

Explanation:

Answer:

mantle

Explanation:

Answer:

double

Explanation:

.

The abundance of isotope 35 = 75%

The abundance of isotope 37 = 25%

Ratio isotope 35 :  isotope 37 = 3 : 1

Given

Ar Cl = 35.5

Two isotopes of mass number 35 and 37

Required

The ratio of each isotope

Solution

If the abundance of isotope 35 is x%, then the abundance of isotope 37 is (100-x)%

35.5 = x%.35 + (100-x)%.37

35.5 = 0.35x+0.37(100-x)

35.5=0.35x-0.37x+37

0.02x=1.5

x=75

Answer:

dic

Explanation:

Answer: these are for questions 1,2,4,5,7

Explanation: number 3: as the pressure in the volume decreases, the volume increases causing it to expand and eventually blow.

number 6: because the temperature and the amount of gas don’t change, these terms don’t appear in the equation. What Boyle’s law means is that the volume of a mass of gas is inversely proportional to its pressure. This linear relationship between pressure and volume means doubling the volume of a given mass of gas decreases its pressure by half.

hope this helps :))

Answer:

I believe Gases A and D

Explanation:

The lines in both gases match up with the lines in the unknown mixture.

Answer:

Fa (rt) and Nitrogen

Explanation:

Answer: Option (b) is the correct answer.

Explanation:

It is known that,

                   pH + pOH = 14

So, pOH = 14 - pH

As the given pH is 9.3. Hence, pOH for the given solution will be calculated as follows.

          pOH = 14 - 9.3

                   = 4.7

Therefore, pOH of the given solution is 4.7.

Answer:

No, you cannot

Explanation:

One of the major properties a cancer drug must have is that, it must be highly specific. If a drug that poisons enzymes of anaerobic metabolism is used on a cancer patient, it should be noted that the drug will not only kill cancer cells but will also kill under cells that make use of anaerobic metabolism. Hence, this drug is not a specific to cancer cells but will also affect other normal cells in the patient's body. Thus, it would be wrong to use such drugs to treat cancer.

Answer:

The sickle cell gene is recessive to the normal gene

Please find the description below

Explanation:

Sickle cell is a blood disease inherited genetically from one's parents. The sickle cell is associated with the blood genotype of an individual. The allele for sickle cell trait is S, while that of the normal gene is A. In this gene, the allele for normal gene (A) is dominant over the allele for sickle cell (S).

Hence, people that have one sickle cell gene (S) and one normal gene (A) will have an AS genotype. The individual will have few defective cells and no symptoms because the phenotypic expression of the sickle cell allele has been masked by the normal one.

Answer:

in sixth period out of 32 elements, 14 elements have been placed separately in horizontal row below periodic table.

Answer:

You need to make sure the number of atoms of each element on the reactant side is equal to the number of atoms of each element on the product side. In order make both sides equal, you will need to multiply the number of atoms in each element until both sides are equal. :)

Answer:

1.389

Explanation:

P = m / V

m = 1250

V = 4x9x25 = 900

1250/900 = 1.388889

Answer:

yes ?

Explanation:

    ...............................

Answer: [tex]_{38}^{90}\textrm{Sr}\rightarrow _{36}^{86}\textrm{Kr}+_2^4\textrm{He}[/tex]

Explanation:

Alpha Decay: In this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. The mass number is reduced by 4 units and atomic number is reduced by 2 units.

General representation of an element is given as:   [tex]_Z^A\textrm{X}[/tex]

where,

Z represents Atomic number

A represents Mass number

X represents the symbol of an element

General representation of alpha decay :

[tex]_Z^A\textrm{Sr}\rightarrow _{Z-2}^{A-4}Y+_2^4\alpha[/tex]

The  balanced nuclear equation when the isotope Strontium-90 decays by Q-  decay is :

[tex]_{38}^{90}\textrm{Sr}\rightarrow _{36}^{86}\textrm{Kr}+_2^4\textrm{He}[/tex]

Answer:

Sublimation is a physical change. When a substance sublimes, it changes from a solid to a gas without going through the liquid phase.

Explanation: