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3 years ago

Oxygen has 8 plus-charged protons. The number of minus-charged electrons is

1 answer:

6 0

A single oxygen has atomic number 8 that means the nuclei of all oxygen atoms have eight protons. The number of minus-charged electron is two but the number of electrons is 10. To gain a minus two-charge ion, it must have two more negative electrons than positive charged protons. With this, the ion has 10 electrons, which give it a -2 net charge.

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Select the correct answer. which tool is used to measure an object’s mass? a. graduated cylinder b. meter stick c. digital therm

zavuch27 [327]

The tool or instrument which is used to measure an object’s mass is electronic balance

Mass is a fundamental quantity

<h3>What is fundamental quantities?</h3>

Fundamental quantities can be defined as those physical quantities which forms the basic unit of measurement. They are the quantities upon which other quantities and units are derived from.

Mass is measured in kilograms (kg)

Other examples of fundamental quantities apart from mass are as follows:

Length
Time
Amount of substances
Luminous intensity
Temperature
Magnetic flux

So therefore, the tool or instrument which is used to measure an object’s mass is electronic balance

Learn more about fundamental/physical quantities:

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6 0

1 year ago

The half-life of cesium-137 is 30 years. Suppose we have a 180 mg sample. Find the mass that remains after t years. Let y(t) be

Stels [109]

Explanation:

1) Initial mass of the Cesium-137= $N_o$ = 180 mg

Mass of Cesium after time t = N

Formula used :

$N=N_o\times e^{-\lambda t}\\\\\lambda =\frac{0.693}{t_{\frac{1}{2}}}$

Half life of the cesium-137 = $t_{1/2}=30 years[p/tex]where,
[tex]N_o$ = initial mass of isotope

N = mass of the parent isotope left after the time, (t)

$t_{\frac{1}{2}}$ = half life of the isotope

$\lambda$ = rate constant

$N=N_o\times e^{-(\frac{0.693}{t_{1/2}})\times t}$

Now put all the given values in this formula, we get

$N=180mg\times e^{-\frac{0.693}{30 years}\times t}$

Mass that remains after t years.

$N=180 mg\times e^{0.0231 year^{-1}\times t}$

Therefore, the parent isotope remain after one half life will be, 100 grams.

t = 70 years

$N_o=180 mg$

$t_{1/2}= 30 yeras$

$N=180mg\times e^{-\frac{0.693}{30 years}\times 70 years}$

N = 35.73 mg

35.73 mg of cesium-137 will remain after 70 years.

$N_o=180 mg$

$t_{1/2}= 30 yeras$

N = 1 mg

t = ?

$1 mg =180mg\times e^{-\frac{0.693}{30 years}\times t}$

$\frac{-30 year}{0.693}\times \ln \frac{1 mg}{180 mg}=t$

t = 224.80 years ≈ 225 years

After 225 years only 1 mg of cesium-137 will remain.

7 0

3 years ago

Which list includes three forms of energy?

loris [4]

I think the correct answer from the choices listed above is option 1. The list that includes three forms of energy would be chemical, mechanical and electromagnetic. Pressure and temperature are not energy. Hope this answers the question. Have a nice day.

5 0

2 years ago

Read 2 more answers

Quick electron emissions are called

vivado [14]

Answer:

Beta decay

Quick electron emissions are called beta decay

Hope this helps

5 0

2 years ago

How many moles are present in 1.75 g of zinc sulfate, Znso, ?

Cerrena [4.2K]

Explanation:

We assume you are converting between grams ZnSO4 and mole. You can view more details on each measurement unit: molecular weight of ZnSO4 or mol This compound is also known as Zinc Sulfate. The SI base unit for amount of substance is the mole. 1 grams ZnSO4 is equal to 0.0061941519772353 mole.

7 0

3 years ago