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3 years ago

How many neutrons does element X have if its atomic number is 23 and its mass number is 87?

2 answers:

6 0

The periodic table, surprisingly, carries much more info than most would think. Each item is in a specific place that accurately puts it into several precise categories at once, which scientists utilize constantly.

In this case, one of those categories is the atomic number and mass number. These together hod the key to finding out the composition of the nucleus.
The atomic number in elements is how many protons are in the nucleus. As you should know, a nucleus contains BOTH protons and neutrons. This is what is represented by the MASS number, which is protons +neutrons. (ignoring anything after the decimal point)

So, if Element has an atomic number (protons) of 23, and a mass number of 87, this means 23+neutrons=87. Do the inverse. 87-23=64
This means element X has 23 protons, 64 neutrons, and 23 electrons (assuming it's electrically neutral).

The answer of neutrons is 64
Hope this helps!

snow_lady [41]3 years ago

5 0

Answer:
100

The atomic mass of an element can be thought of as the number of protons + the number of neutrons. The atomic number of an element equals the amount of protons it has. Using this, we see that the number of neutrons can be calculated by subtracting the atomic number from the atomic mass. In this case, we get
153
−
53
=
100
.

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The Law of _____states that substances combine in predictable proportions and that excess reactants remain unchanged.

RideAnS [48]

Answer: definite proportions.

Explanation:

1) The definite proportions law states that compounds will always have the same kind of atoms (elements) in the same mass proportion (ratios).

2) For example, a molecule of water will alwys have the same mass ratio of hydrogen atoms to oxygen atoms. That is what permits to obtain the chemical formula of the water molecule as H₂O.

The mass of the two hydrogen atoms will be in a fixed ratio respect to the mass of the oxygen atoms.

Then, if you have one reactant in less proportion than the other, respect to the ratio stated by the chemical formula of water, the former will react completely (it is the limiting reactant) with the corresponding (proportional) mass of the later. Then there will be an excess of the later reactant which will not react (will remain unchanged).

The reactants can only react in the proportion defined by the chemical formulas of the final products.

4 0

3 years ago

Read 2 more answers

When 6.040 grams of a hydrocarbon, CxHy, were burned in a combustion analysis apparatus, 18.95 grams of CO2 and 7.759 grams of H

algol [13]

Answer: The empirical formula is $CH_2$ and molecular formula is $C_4H_8$

Explanation:

We are given:

Mass of $CO_2$ = 18.95 g

Mass of $H_2O$ = 7.759 g

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in 18.59 g of carbon dioxide, = $\frac{12}{44}\times 18.59=5.07g$ of carbon will be contained.

For calculating the mass of hydrogen:

In 18g of water, 2 g of hydrogen is contained.

So, in 7.759 g of water, = $\frac{2}{18}\times 7.759=0.862g$ of hydrogen will be contained.

Mass of C = 5.07 g

Mass of H = 0.862 g

Step 1 : convert given masses into moles.

Moles of C = $\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{5.07g}{12g/mole}=0.422moles$

Moles of H= $\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{0.862g}{1g/mole}=0.862moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = $\frac{0.422}{0.422}=1$

For H = $\frac{0.862}{0.422}=2$

The ratio of C : H = 1: 2

Hence the empirical formula is $CH_2$ .

The empirical weight of $CH_2$ = 1(12)+2(1)= 14 g.

The molecular weight = 56.1 g/mole

Now we have to calculate the molecular formula.

$n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{56.1}{14}=4$

The molecular formula will be= $4\times CH_2=C_4H_8$

6 0

3 years ago

Calculate the mass of .0605 moles of crystalline sucrose. Sucrose is C12 H22 O11 . The molar mass is __________ g/mole. Show you

KengaRu [80]

Answer:

20.7g/mol

Explanation:

7 0

3 years ago

Herbicides break down dead organisms into humus. True or False?

Rzqust [24]

Answer:

true

Explanation:

8 0

3 years ago

What is the volume (in liters) occupied by 49.8 g og HCl at STP

Anon25 [30]

Using ideal gas equation,

P\times V=n\times R\times T

Here,

P denotes pressure

V denotes volume

n denotes number of moles of gas

R denotes gas constant

T denotes temperature

The values at STP will be:

P=1 atm

T=273 K

R=0.0821 atm L mol ⁻¹

Mass of HCl given= 49.8 g

Molar mass of HCl given=36.41

Number of moles of gas, n= \frac{Given mass of the substance}{Molar mass of the substance}

Number of moles of gas, n= \frac{49.8}{36.46}

Number of moles of gas, n= 1.36

Putting all the values in the above equation,

V=\frac{1.36\times 0.0821\times 273}{1}

V=30.6 L

So the volume will be 30.6 L.

6 0

3 years ago