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Tresset [83]
3 years ago
12

The half-life of sodium-24 is 15 days. A laboratory technician measures out a 72 g sample. Approximately how many grams of sodiu

m-24 would remain after 45 days?
Chemistry
1 answer:
Vanyuwa [196]3 years ago
6 0

Answer:

after 45 days 9 g left

Explanation:

Given data:

Half life Na-24 = 15 days

Mass of sample = 72 g

Mass remain after 45 days = ?

Solution:

Number of half lives passed:

Number of half lives = time elapsed / half life

Number of half lives = 45 days / 15 days

Number of half lives = 3

At time zero total amount = 72 g

After first half life = 72 g/ 2= 36 g

At 2nd half life = 36 g/2 = 18 g

At 3rd half life = 18 g/2 = 9 g

Thus after 45 days 9 g left.

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Les étapes nous permettant de sentir une tarte aux pommes
Dmitry [639]

Answer:

L'ordre correct est le suivant;

1. Les cils olfactifs capturent les molécules chimiques odorantes

2. Le signal des molécules chimiques est transformé en impulsions nerveuses

3. L'influx nerveux est transféré au cerveau par le nerf olfactif au bulbe olfactif du cerveau antérieur

4. Les odeurs sont perçues

Explanation:

Pour sentir la pomme, l'air autour de la pomme est inhalé rapidement pour aider les produits chimiques odorants à entrer dans la cavité nasale.

La cavité nasale a des cellules spéciales qui sont réceptives aux produits chimiques odorants, qui envoient un message au cerveau lors de la liaison au produit chimique par le nerf olfactif. Lorsque le message arrive au bulbe olfactif du cerveau antérieur, il est analysé et l'odeur est identifiée et / ou reconnue.

Par conséquent, l'ordre correct est le suivant;

1. 1. Les cils olfactifs captent les molécules chimiques odorantes

2. 2. Le signal des molécules chimiques est transformé en impulsions nerveuses

3. 4. L'influx nerveux est transféré au cerveau par le nerf olfactif au bulbe olfactif du cerveau antérieur

4. 3. Les odeurs sont perçues.

3 0
3 years ago
Choose the covalent compounds from the following choices Br2 MgS SO2 KF
Novosadov [1.4K]

Types of Bonds can be predicted by calculating the difference in electronegativity.

If, Electronegativity difference is,

 

                Less than 0.4 then it is Non Polar Covalent Bond

                

                Between 0.4 and 1.7 then it is Polar Covalent Bond

            

                Greater than 1.7 then it is Ionic

 

For Br₂;

                    E.N of Bromine      =   2.96

                    E.N of Bromine      =   2.96

                                                   ________

                    E.N Difference             0.00          (Non Polar Covalent Bond)


For MgS;

                    E.N of Sulfur               =   2.58

                    E.N of Magnesium      =   1.31

                                                   ________

                    E.N Difference                  1.27          (Ionic Bond)


For SO₂;

                    E.N of Oxygen      =   3.44

                    E.N of Sulfur          =   2.58

                                                   ________

                    E.N Difference             0.86          (Polar Covalent Bond)


For KF;

                    E.N of Fluorine          =   3.98

                    E.N of Potassium      =   0.82

                                                   ________

                    E.N Difference                3.16          (Ionic Bond)

Result: The Bonds in Br₂ and SO₂ are Covalent in Nature.

3 0
3 years ago
The mass of 0.10 mole of methane
saveliy_v [14]

Answer:

A methane molecule is made from one carbon atom and four hydrogen atoms. Carbon has a mass of 12.011 u and hydrogen has a mass of 1.008 u. This means that the mass of one methane molecule is 12.011 u + (4 × 1.008u), or 16.043 u. This means that one mole of methane has a mass of 16.043 grams.

メタン分子は、1つの炭素原子と4つの水素原子から作られています。炭素の質量は12.011uで、水素の質量は1.008uです。これは、1つのメタン分子の質量が12.011 u +(4×1.008u)、つまり16.043uであることを意味します。これは、1モルのメタンの質量が16.043グラムであることを意味します。^>^

5 0
3 years ago
Which of the following diagrams represents a single<br> replacement reaction?
kari74 [83]

Answer:

It's a, trust me I'm very good with chemistry

3 0
1 year ago
What is the definition of physical science?
katovenus [111]

Answer:

The definition of physical science is the sciences concerned with the study of inanimate natural objects, including physics, chemistry, astronomy, and related subjects.

Explanation:

7 0
3 years ago
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