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3 years ago

Why are valence electrons used in chemical bonding?

Physics

2 answers:

Phoenix [80]3 years ago

4 0

I think it’s A. Hope it helps

andrezito [222]3 years ago

4 0

A is the answer ......... and

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the volume of ice block is 2400cm^3 and its density is 0.9 g/cm^3. how much part of it remains above the surface of water when i

stiks02 [169]

Answer:

240 cm³

Explanation:

Weight = Buoyancy

mg = ρVg

m = ρV

(0.9 g/cm³ × 2400 cm³) = (1 g/cm³) V

V = 2160 cm³

The submerged volume is 2160 cm³, so the volume above the surface is 240 cm³.

4 0

3 years ago

At t= 0, a particle moving in the xy plane with constant acceleration has a velocity of Vi= (3.00i -2.00j) m/s and is at the ori

ivanzaharov [21]

Answer:

(a) a = (2i + 4.5j) m/s^2

(b) r = ro + vot + (1/2)at^2

Explanation:

(a) The acceleration of the particle is given by:

$\vec{a}=\frac{\vec{v}-\vec{v_o}}{t}\\\\$

vo: initial velocity = (3.00i -2.00j) m/s

v: final velocity = (9.00i + 7.00j) m/s

t = 3s

by replacing the values of the vectors and time you obtain:

$\vec{a}=\frac{1}{3s}[(9.00-3.00)\hat{i}+(7.00-(-2.00))\hat{j}]\\\\\vec{a}=(2\hat{i}+4.5\hat{j})m/s^2$

(b) The position vector is given by:

$\vec{r}=\vec{r_o}+\vec{v_o}t+\frac{1}{2}\vec{a}t^2$

where vo = (3.00i -2.00j) m/s and a = (2.00i + 4.50j)m/s^2

4 0

3 years ago

A cup of hot coffee initially at 95 degrees C cools to 80 degrees C in 5 min while sitting in a room of temperature 21 degrees C

Oksana_A [137]

Answer:

When the temperature of the coffee is 50 °C, the time will be 20.68 mins

Explanation:

Given;

The initial temperature of the coffee T₀ = 95 °C

The temperature of the room = 21°C

Let T be the temperature at time of cooling t in mins

According to Newton's law of cooling;

$\frac{dT}{dt} \alpha (T-21)\\\\\frac{dT}{dt} = k (T-21)\\\\\frac{dT}{T-21} = kdt\\\\\int\limits {\frac{dT}{T-21}} = \int\limits kdt\\\\Log(T-21) =kt + Logc \\\\Log (\frac{T-21}{c} ) = kt\\\\T -21 = ce^{kt}\\\\At \ t = 0, T = 95\\\\95-21 = ce^0\\\\74 = c\\\\New, equation: T -21 = 74e^{kt}\\\\Again; when \ t= 5\ min, T = 80\\\\80 -21 = 74e^{5k}\\\\59 = 74e^{5k}\\\\e^{5k} = \frac{59}{74}\\\\ 5k = ln(\frac{59}{74})\\\\5k = -0.2265\\\\k = -0.0453$

When the temperature is 50 °C, the time t in min is calculated as;

$T -21 = 74e^{-0.0453t}\\\\50 -21 = 74e^{-0.0453t}\\\\29 = 74e^{-0.0453t}\\\\\frac{29}{74} = e^{-0.0453t}\\\\0.39189 = e^{-0.0453t}\\\\ln(0.39189 ) = {-0.0453t}\\\\-0.93677 = {-0.0453t}\\\\t = \frac{-0.93677}{-0.0453}\\\\ t = 20.68 \ mins$

Therefore, when the temperature of the coffee is 50 °C, the time will be 20.68 mins

4 0

3 years ago

What color do blind people see lol

Pachacha [2.7K]

Answer

I think most see black and white.

5 0

3 years ago

Read 2 more answers

An object moving at 30 m/s takes 5s to come to a stop. what is the object's acceleration?

Taya2010 [7]

Use SUVAT where:
S = distance
U = initial velocity = 30m/s
V = end velocity = 0 m/s
A = acceleration = ?
T = time = 5 secs

then pick out the equation v = u + at

so:
0 = 30 + 5a
-30 / 5 = a
a = -6 m/s^2

4 0

3 years ago