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2 years ago

Which scientist is known for developing the planetary model of the atom

Chemistry

1 answer:

xenn [34]2 years ago

7 0

Answer:

Ernest Rutherford

Explanation:

The Rutherford model, proposed originally in 1911, dipicts a planetary model of the atom in which there is a nucleus and electrons circling it.

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If a candle is burning in an open room, which reactant is in excess?

LenKa [72]

Answer:

Explanation:

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3 years ago

A first-order reaction (A → B) has a half-life of 25 minutes. If the initial concentration of A is 0.900 M, what is the concentr

Oksanka [162]

Answer:

0.6749 M is the concentration of B after 50 minutes.

Explanation:

A → B

Half life of the reaction = $t_{1/2}=25 minutes$

Rate constant of the reaction = k

For first order reaction, half life and half life are related by:

$k=\frac{0.693}{t_{1/2}}$

$k=\frac{0.693}{25 min}=0.02772 min^{-1}$

Initial concentration of A = $[A]_o=0.900 M$

Final concentration of A after 50 minutes = $[A]=?$

t = 50 minute

$[A]=[A]_o\times e^{-kt}$

$[A]=0.900 M\times e^{-0.02772 min^{-1}\times 50 minutes}$

[A] = 0.2251 M

The concentration of A after 50 minutes = 0.2251 M

The concentration of B after 50 minutes = 0.900 M - 0.2251 M = 0.6749 M

0.6749 M is the concentration of B after 50 minutes.

7 0

3 years ago

A gecko used its sticky feet to crawl from the bottom of a window to the top of

sp2606 [1]

Answer:

Decreased

Explanation:

You're faster when you go downhill than you are uphill.

8 0

3 years ago

How much heat is needed to melt 100.0 grams of ice that is already at 0°C?

Rashid [163]

A. The heat is needed to melt 100.0 grams of ice that is already at 0°C is +33,400 J.

<h3>What is Specific heat capacity?</h3>

Specific heat capacity is the quantity of heat needed to raise the temperature per unit mass.

<h3>Heat needed to melt the cube of ice</h3>

The heat is needed to melt 100.0 grams of ice that is already at 0°C is calculated as follows;

Q = mL

where;

m is mass of the ice
L is latent heat of fusion of ice = 334 J/g

Q = 100 x 334

Q = 33,400 J

Thus, the heat is needed to melt 100.0 grams of ice that is already at 0°C is +33,400 J.

Learn more about heat capacity here: brainly.com/question/16559442

#SPJ1

6 0

11 months ago

Name two ways adding salt to lower the freezing temperature benefits you.

miss Akunina [59]

Answer:

Explanation:

Lowers freezing point

3 0

2 years ago

Read 2 more answers