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3 years ago

15

What is the percent composition of a copper chloride compound if a 269 g sample contains 127 g of copper and 142 grams of chlori

ne.

1 answer:

Tems11 [23]3 years ago

5 0

Answer:

Explanation:

The whole sample is 269

%copper = 127/269 * 100 = 47.2%

%chlorine = 142/269 * 100 = 52.8%

That's all you are asking. Is there more?

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How many atoms of hydrogen are there in 18g of water ?

Bingel [31]

Answer:

They are 1.204×10^24 atoms of hydrogen present in 18 grams of water. In order to calculate this,it is necessary to compute the number of hydrogen moles present in the sample.

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2 years ago

A wooden tool is found at an archaeological site. Estimate the age of the tool using the following information: A 100 gram sampl

lord [1]

Answer:

2578.99 years

Explanation:

Given that:

100 g of the wood is emitting 1120 β-particles per minute

Also,

1 g of the wood is emitting 11.20 β-particles per minute

Given, Decay rate = 15.3 % per minute per gram

So,

Concentration left can be calculated as:-

C left = $[A_t]=\frac{11.20\ per\ minute}{15.3\ per\ minute\ per\ gram}\times [A_0]= 0.7320[A_0]$

Where,

$[A_t]$ is the concentration at time t

$[A_0]$ is the initial concentration

Also, Half life of carbon-14 = 5730 years

$t_{1/2}=\frac {ln\ 2}{k}$

Where, k is rate constant

So,

$k=\frac {ln\ 2}{t_{1/2}}$

$k=\frac {ln\ 2}{5730}\ years^{-1}$

The rate constant, k = 0.000120968 year⁻¹

Time =?

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

So,

$\frac {[A_t]}{[A_0]}=e^{-0.000120968\times t}$

$\frac {0.7320[A_0]}{[A_0]}=e^{-0.000120968\times t}$

$0.7320=e^{-0.000120968\times t}$

$ln\ 0.7320=-0.000120968\times t$

<u>t = 2578.99 years</u>

8 0

3 years ago

Write the complete symbol, including mass number and atomic number, for each atom.

Reil [10]

Answer:

a) 58Ni

b) 43Ti

c) 34P

d) 18O

e) 58Ni

f) 43Ti

g)34P

h) 18O

i) 54Cr

Explanation:

<em>a) contains 28 protons and 30 neutrons:</em>

An atom with 28 protons and 30 neutrons has an atomic number of 28 and a mass number of (30+28) = 58.

The atom with atomic number 28 is Ni.

<em>b) contains 22 protons and 21 neutrons:</em>

An atom containing 22 protons and 21 neutrons has an atomic number of 22 and an atomic mass of (22+21) = 43

The atom with atomic number 22 is Titanium (Ti).

This is the 43Ti isotope of titanium

<em>c) contains 15 electrons and 19 neutrons</em>

An atom with 15 electrons would have the same amount of , 15 protons (considering it to be neutral) and has 19 neutrons.

Thus, the atomic number of the atom would be 15 and the mass number would be (15+19) = 34

The atom with atomic number 15 is phosphorus (P).

This is the 34P isotope of phosphorus

<em>d) an oxygen atom with 10 neutrons:</em>

Oxygen has an atomic number of 8, thus there are 8 protons in an atom of oxygen.

The mass number of the oxygen atom with 10 neutrons would be (8+10) = 18

This is 18O - isotope.

<em>e) contains 28 protons and 30 neutrons:</em>

An atom with 28 protons and 30 neutrons has an atomic number of 28 and a mass number of (30+28) = 58.

The atom with atomic number 28 is Ni.

<em>f) contains 22 protons and 21 neutrons:</em>

An atom containing 22 protons and 21 neutrons has an atomic number of 22 and an atomic mass of (22+21) = 43

The atom with atomic number 22 is Titanium (Ti).

This is the 43Ti isotope of titanium

<em>g) contains 15 electrons and 19 neutrons:</em>

An atom with 15 electrons would have the same amount of , 15 protons (considering it to be neutral) and has 19 neutrons.

Thus, the atomic number of the atom would be 15 and the mass number would be (15+19) = 34

The atom with atomic number 15 is phosphorus (P).

This is the 34P isotope of phosphorus

<em>h) an oxygen atom with 10 neutrons:</em>

Oxygen has an atomic number of 8, thus there are 8 protons in an atom of oxygen.

The mass number of the oxygen atom with 10 neutrons would be (8+10) = 18

This is 18O - isotope.

<em>i) The atomic number of Cr is 24 </em>

The mass number is given to be 54.

This is the 54Cr isotope and has 24 protons and 30 neutrons

8 0

3 years ago

How do hormones travel throughout our body?

EleoNora [17]

Hormones travel through the body by using blood streams, such as veins. The hormones then get to the target cell by moving through the liquids surrounding the cells. They then change how the cell works, thus changing the body.

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3 years ago

When calcium metal is placed in water, hydrogen gas bubbles out, leaving a highly alkaline (basic) solution. Write the balanced

Blababa [14]

Answer:

Ca (s) + 2H₂O (l) → Ca(OH)₂ (aq) + H₂ (g)

Explanation:

When solid calcium reacts with water, it produces the correspondent hydroxid and hydrogen gas.

The hydroxid which is produced, is the calcium hydroxid which is a strong base, that's why you talk about a highly alkaline solution.

Ca (s) + 2H₂O (l) → Ca(OH)₂ (aq) + H₂ (g)

Calcium hydroxide is a strong base, that dissociates in water, as this:

Ca(OH)₂ → Ca²⁺ (aq) + 2OH⁻ (aq)

It's a basic solution, is providing hydroxyl ions to the medium

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3 years ago