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3 years ago

In which situation is the acceleration of the car negative?

Chemistry

2 answers:

Llana [10]3 years ago

4 0

Answer is: B.)The velocity of a car reduced from 50 km/h over one minute.

Ending velocity is defined as the velocity attained by a body after completing distance at certain time interval:

v(ending velocity) = v(initial velocity) + a·t.

a is acceleration attained by the body (in this examle car).

t is time (in this example one minute).

Because velocity is reduced, acceleration has negative sign.

An car average acceleration over a period of time is its change in velocity.

Charra [1.4K]3 years ago

3 0

B) The velocity of the car reduced from 50k/m over one min.

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A reaction was suppose to produce 20 L of gas. Only 12 litters of gas were produced in the lab. What is the percent yield for th

pogonyaev

Answer:

$\boxed {\boxed {\sf 60 \%}}$

Explanation:

Percent yield is a ratio of the actual yield to the theoretical yield. It is found using this formula:

$\% \ yield= \frac {actual \ yield}{theoretical \ yield} *100$

The actual yield is 12 liters, because that was actually produced in the lab.

The theoretical yield is 20 liters, because that was the expected yield.

$\% \ yield= \frac {12 \ L}{20\ L} *100$

$\% \ yield= 0.6*100$

$\% \ yield= 60$

For this reaction, the percent yield is 60%.

5 0

2 years ago

What are some differences between Boiling & Evaporation?

Angelina_Jolie [31]

Boiling happens much faster! Boiling also takes place at the bottom of the fluid whereas evaporation takes place at the top.

Hope this helps!

3 0

3 years ago

Read 2 more answers

What is FeCl3+NaOH=Fe(OH)3+NaCl

nasty-shy [4]

This type of formula is use in chemistry it has Iron ,Sodium, Hydroxyl and Chloride unit s in the equation.
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3 0

3 years ago

The sun shines with equal intensity on a farm field, an asphalt road, and the ocean. Which material will heat up most during the

Stolb23 [73]

Answer:

The sun shines with equal intensity on a farm field, an asphalt road and the ocean. So basically asphalt road are heated the most during the day

Explanation:

The heat of water is more than the specific heat of sand.

Therefore sand is hot.

.Water is reflecting solar radiation.

The land retains more heat since the land absorb solar radiation.

Therefore the land surfaces warm faster.

Since water is a slow conductor of heat, it need more energy than the sand. so its temperature is increasing. soil loses heat faster.

The ocean heats slower than land , the land air is more warmer than lean air. After the sun set the land loses heat quickly .The air above it cools.

8 0

3 years ago

A sample of gas is observed to effuse through a pourous barrier in 4.98 minutes. Under the same conditions, the same number of m

kogti [31]

Answer:

The molar mass of the unknown gas is $\mathbf{ 51.865 \ g/mol}$

Explanation:

Let assume that the gas is O2 gas

O2 gas is to effuse through a porous barrier in time t₁ = 4.98 minutes.

Under the same conditions;

the same number of moles of an unknown gas requires time t₂ = 6.34 minutes to effuse through the same barrier.

From Graham's Law of Diffusion;

Graham's Law of Diffusion states that, at a constant temperature and pressure; the rate of diffusion of a gas is inversely proportional to the square root of its density.

i.e

$R \ \alpha \ \dfrac{1}{\sqrt{d}}$

$R = \dfrac{k}{d}$ where K = constant

If we compare the rate o diffusion of two gases;

$\dfrac{R_1}{R_2}= {\sqrt{\dfrac{d_2}{d_1}}$

Since the density of a gas d is proportional to its relative molecular mass M. Then;

$\dfrac{R_1}{R_2}= {\sqrt{\dfrac{M_2}{M_1}}$

Rate is the reciprocal of time ; i.e

$R = \dfrac{1}{t}$

Thus; replacing the value of R into the above previous equation;we have:

$\dfrac{R_1}{R_2}={\dfrac{t_2}{t_1}}$

We can equally say:

${\dfrac{t_2}{t_1}}= {\sqrt{\dfrac{M_2}{M_1}}$

${\dfrac{6.34}{4.98}}= {\sqrt{\dfrac{M_2}{32}}$

$M_2 = 32 \times ( \dfrac{6.34}{4.98})^2$

$M_2 = 32 \times ( 1.273092369)^2$

$M_2 = 32 \times 1.62076418$

$\mathbf{M_2 = 51.865 \ g/mol}$

7 0

2 years ago