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3 years ago

What happens to the mass of a sample containing a radioactive element during its half-life?

1 answer:

6 0

Of course, the mass remains the same for practical purposes. During the release of energy, a very tiny portion of mass is converted to energy, but that mass is extremely small, and cannot be determined by ordinary means.

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g A solution contains 100mM NaCl, 20mM CaCl2, and 20mM urea. We would say this solution is __________ compared to a 300 mOsM sol

ICE Princess25 [194]

Answer:

A solution contains 100mM NaCl, 20mM CaCl2, and 20mM urea. We would say this solution is hypotonic compared to a 300 mOsM solution and hypotonic compared to a cell with 300 mOsM (non-penetrating solutes) interior.

Explanation:

The osmolarity is calculated from the molar concentration of the active particles in the solution. We have a solution that is composed of NaCl, CaCl₂ and urea.

When they are dissolved in water, they dissociate into particles as follows:

NaCl → Na⁺ + Cl⁻ (2 particles per compound)

CaCl₂ → Ca²⁺ + 2 Cl⁻ (3 particles per compound)

urea: not dissociation (1 particle per compound)

Then, we have to calculate the osmolarity of the solution. We multiply the molarity of each compound by the number of particles produced by the compound in water:

Osm = (100 mM NaCl x 2) + (20 mM CaCl₂ x 3) + (20 mM urea x 1) = 280 mOsm

Compared with 300 mOsm, 280 mOsm has a lower osmolarity, so it is a hypotonic solution.

To compare with a cell's osmolarity, we have to consider only the non-penetrating solutes. Urea is considered a penetrating solute for mammalian cells. So, the osmolarity of non-penetrating solutes (NaCl and CaCl₂) is calculated as:

Osm (non-penetrating solutes) = (100 mM NaCl x 2) + (20 mM CaCl₂ x 3) = 260 mOsm

Therefore, we have:

Compared to 300 mOsm solution ⇒ 280 mOsm solution is a hypotonic solution

Compared to a cell with 300 mOsm ⇒ 260 mOsm solution is hypotonic

4 0

3 years ago

What is the specific heat of a substance that absorbs 2500 joules of heat when a sample of 100g of the substance increases in te

Ierofanga [76]

Answer:

0.417 J/gºC

Explanation:

From the question given above, the following data were obtained:

Heat (Q) absorbed = 2500 J

Mass (M) of substance = 100 g

Initial temperature (T1) = 10 °C

Final temperature (T2) = 70 °C

Specific heat capacity (C) =?

Next, we shall determine the change in temperature (ΔT). This can be obtained as follow:

Initial temperature (T1) = 10 °C

Final temperature (T2) = 70 °C

Change in temperature (ΔT) =?

Change in temperature (ΔT) = T2 – T1

Change in temperature (ΔT) = 70 – 10

Change in temperature (ΔT) = 60 °C

Finally, we shall determine the specific heat capacity of the substance as follow:

Heat (Q) absorbed = 2500 J

Mass (M) of substance = 100 g

Change in temperature (ΔT) = 60 °C

Specific heat capacity (C) =?

Q = MCΔT

2500 = 100 × C × 60

2500 = 6000 × C

Divide both side by 6000

C = 2500 / 6000

C = 0.417 J/gºC

Therefore, the specific heat capacity of substance is 0.417 J/gºC

5 0

3 years ago

What is the result of multiplying (2.5 × 1010) × (3.5 × 10-7)? Use the correct number of significant digits.

kow [346]

the result of multiplying (2.5 × 10¹⁰) and (3.5 × 10⁻⁷) is 8.8.10³ (cause the result must have 2 significant number)

<h3><em>Further Explanation</em> </h3>

Significant numbers are numbers obtained from the measurement results of exact numbers and the last number estimated

In scientific notation, all numbers are displayed before the big order is called significant numbers

the scientific notation can be described as:

a, ... x 10ⁿ

a, ... called an important number

10ⁿ is called a big order

Rules for significant numbers in general:

1. all non-zero numbers are significant numbers

2. a zero which is located between two non-zero numbers including a significant number

3. all zeros are located in the final row written behind the decimal point include significant number

4. zero decimal point is not significant number

In the question it is known that (2.5 × 10¹⁰) and (3.5 × 10⁻⁷) both have a significant number in a row 2.5 and 3.5

so that it meets the rule of significant numbers which is multiplication of 2 significant number produces numbers that have the fewest significant numbers, So the multiplication of the two will produce 2 significant number

So that we do the significant number then proceed a big order

1. Multiplication of significant number2.5 x 3.5 = 8.75

2. a big order multiplication 10¹⁰ x 10⁻⁷ = 10¹⁰⁻⁷ = 10³

So the result = 8.75.10³

Because the result must have 2 significant number , the result is 8.8.10³ (8.75 we round up)

<h3><em> Learn more</em></h3>

significant figures brainly.com/question/11151926

significant figures in the following number: 5.67 x 106 brainly.com/question/7539478

the number of significant figures is 0.025 brainly.com/question/10343704

0.080 significant figures brainly.com/question/1999241

the fewest number of significant figures brainly.com/question/11464470

5 0

3 years ago

Read 2 more answers

Hey, I’ll give brainliest. Just please help.

Andre45 [30]

Answer:

Explanation:

8 0

3 years ago

the results have been archived so far in relation to the problem with the given fact relevant and measurable

Rama09 [41]

Where’s the problem I know how to do it

8 0

3 years ago