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3 years ago

How did Bohr describe the arrangement of particles within an atom?

Chemistry

2 answers:

alexandr1967 [171]3 years ago

4 0

Answer: A

Explanation: Protons and neutrons form the nucleus of the atom, with electrons orbiting it.

ladessa [460]3 years ago

4 0

Answer:

a is the correct choice

Explanation:

this is the right answer on apex, if you look it up anywhere else its also the right answer.

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Nikolas, the fire extinguisher, and the skateboard have a combined mass of 50 kg. What force would the fire extinguisher have to

murzikaleks [220]

Answer:

Force used by fire extinguisher = 60 N

Explanation:

Given:

Mass of skateboard with fire extinguisher = 50 kg

Acceleration of fire extinguisher = 1.2 m/s²

Find:

Force used by fire extinguisher = ?

Computation:

⇒ Force = Mass × Acceleration

⇒ Force used by fire extinguisher = Mass of skateboard with fire extinguisher × Acceleration of fire extinguisher

⇒ Force used by fire extinguisher = 50 kg × 1.2 m/s²

⇒ Force used by fire extinguisher = 60 N

3 0

3 years ago

Read 2 more answers

Starch and cellulose are both produced by plants, yet one is easily digested by animals and the other is not. Discuss the differ

Nadusha1986 [10]

Starch and cellulose have the same substance but different structures. They are both polysaccharides. The basic unit of a polysaccharide is the glucose. Glucose, which contains carbon, hydrogen, and oxygen, have two forms. The alpha-glucose with an alcohol group attached to carbon 1 is down and the beta-glucose with the alcohol group attached to carbon 1 is up. Starch is the alpha-glucose while cellulose is the beta-glucose. Starches are linked into a straight chain whereas the cellulose are connected like a pile of stack paper. When the human body eats starch, it can digest the starch but not the cellulose because it has no enzyme that can break it down.

4 0

3 years ago

A scientist measures the standard enthalpy change for the following reaction to be -17.2 kJ : Ca(OH)2(aq) 2 HCl(aq)CaCl2(s)

elixir [45]

Answer: $\Delta H^{0}=-173.72$ kJ/mol

Explanation: Enthalpy Change is the amount of energy in a reaction - absorption or release - at a constant pressure. So, Standard Enthalpy of Formation is how much energy is necessary to form a substance.

The standard enthalpy of formation of HCl is calculated as:

$\Delta ^{0}=\Sigma H_{products}-\Sigma H_{reactants}$

$Ca(OH)_{2}_{(aq)}+2HCl_{(aq)}$ → $CaCl_{2}_{(s)}+2H_{2}O_{(l)}$

Standard Enthalpy of formation for the other compounds are:

Calcium Hydroxide: $\Delta H^{0}=$ -1002.82 kJ/mol

Calcium chloride: $\Delta H^{0}=$ -795.8 kJ/mol

Water: $\Delta H^{0}=$ -285.83 kJ/mol

Enthalpy is given per mol, which means we have to multiply by the mols in the balanced equation.

Calculating:

$-17.2=[-795.8+2(285.85)]-[-1002.82+2\Delta H]$

$-17.2=-1367.46+1002.82-2\Delta H$

$2\Delta H=17.2-364.64$

$\Delta H=-173.72$

So, the standard enthalpy of formation of HCl is -173.72 kJ/mol

8 0

3 years ago

What are compounds????????????????

sweet [91]

Answer:

Compounds are pure substance consisting of two or more different atoms

8 0

3 years ago

Read 2 more answers

Determine whether the following hydroxide ion concentrations ([OH−]) correspond to acidic, basic, or neutral solutions by estima

Rzqust [24]

Answer:

See explanation below

Explanation:

To do this, we will use the following expression to calculate the [H⁺]:

[H⁺] = Kw / [OH⁻]

[H⁺] is the same as [H₃O⁺]. So we have the [OH⁻] so, let's replace every value into the above expression to calculate the hydronium concentration and say if it's acidic, basic or neutral. This can be known because if the [H⁺] > 1x10⁻⁷ M the solution is acidic. If it's [H⁺] < 1x10⁻⁷ M the solution is basic, and if it's [H⁺] = 1x10⁻⁷ M the solution is neutral.

a) [H⁺] = 1x10⁻¹⁴ / 6x10⁻¹² = 1.67x10⁻³ M. Acidic.

b) [H⁺] = 1x10⁻¹⁴ / 9x10⁻⁹ = 1.11x10⁻⁶ M. Acidic.

c) [H⁺] = 1x10⁻¹⁴ / 8x10⁻¹⁰ = 1.25x10⁻⁵ M. Acidic.

d) [H⁺] = 1x10⁻¹⁴ / 7x10⁻¹³ = 0.0143 M. Acidic.

e) [H⁺] = 1x10⁻¹⁴ / 2x10⁻² = 5x10⁻¹³ M. Basic.

f) [H⁺] = 1x10⁻¹⁴ / 9x10⁻⁴ = 1.11x10⁻¹¹ M. Basic.

g) [H⁺] = 1x10⁻¹⁴ / 5x10⁻⁵ = 2x10⁻¹⁰ M. Basic.

h) [H⁺] = 1x10⁻¹⁴ / 1x10⁻⁷ = 1x10⁻⁷ M. Neutral.

Part B.

In this part, we'll use the following expression and replace the given values:

[OH⁻] = Kw / [H⁺]

Replacing the values:

[OH⁻] = 1x10⁻¹⁴ / 5.2x10⁻⁵

[OH⁻] = 1.92x10⁻¹⁰ M

PArt C:

In this case, we will use expression of part A, and replace the given values:

[H⁺] = 1x10⁻¹⁴ / 2.7x10⁻²

[H⁺] = 3.7x10⁻¹³ M

8 0

3 years ago