Which describes Bohr’s contribution to the atomic model?

Brenda rode a skateboard 95 meters west. It took her 20 seconds. What was

Artemon [7]

Answer:

D. 4.75 m/s west

Explanation:

You can immediately get the answer once you know the formula for velocity.

The formula for velocity is: Velocity (V) = $\frac{distance (d)}{time (t)}$

The distance is 95 meters while the time is 20 seconds. All you have to do is to divide 95 meters by 20 seconds.

Let's solve:

V = $\frac{d}{t}$

V = $\frac{95 meters}{20 seconds}$

V = 4.75 meters per second

Since Brenda is going west with her her skateboard, then you have to add west as her direction.

Brenda's velocity is 4.75 m/s west.

5 0

2 years ago

If it takes 20.4 mL of NaOH(aq) to reach the equivalence point of the titration, what is the molarity of H2SO4(aq)? For your ans

Alik [6]

Question is incomplete, complete question is;

A 34.8 mL solution of $H_2SO_4$ (aq) of an unknown concentration was titrated with 0.15 M of NaOH(aq).

$H_2SO_4(aq)+2NaOH(aq)\rightarrow Na_2SO_4(aq)+2H_2O(l)$

If it takes 20.4 mL of NaOH(aq) to reach the equivalence point of the titration, what is the molarity of $H_2SO_4(aq)$ ? For your answer, only type in the numerical value with two significant figures. Do NOT include the unit.

Answer:

0.044 M is the molarity of $H_2SO_4$ (aq).

Explanation:

The reaction taking place here is in between acid and base which means that it is a neutralization reaction .

To calculate the concentration of acid, we use the equation given by neutralization reaction:

$n_1M_1V_1=n_2M_2V_2$

where,

$n_1,M_1\text{ and }V_1$ are the n-factor, molarity and volume of acid which is $H_2SO_4$

$n_1,M_2\text{ and }V_2$ are the n-factor, molarity and volume of base which is NaOH.

We are given:

$n_1=2\\M_1=?\\V_1=34.8 mL\\n_2=1\\M_2=0.15 M\\V_2=20.4 mL$

Putting values in above equation, we get:

$2\times M_1\times 34.8 mL=1\times 0.15 M\times 20.4 mL\\\\M_1=\frac{1\times 0.15 M\times 20.4 mL\times 10}{2\times 34.8 mL}=0.044 M$

0.044 M is the molarity of $H_2SO_4$ (aq).

4 0

3 years ago

While conducting a lab experiment, Ali calculated that 1.20 E6 Joules of heat were needed to melt 18.5 kilograms of an unknown s

nordsb [41]

Answer:

Latent heat of fusion of the substance is $6.49\times 10^{4}J/kg$

Explanation:

Latent heat of fusion denotes amount of energy (heat) per unit mass required to melt a solid material at constant temperature and pressure i.e. at it's melting point

Here amount of heat required = $1.20\times 10^{6}J$

Mass of unknown substance being melted = 18.5 kg

So, latent heat of fusion of the substance = (required heat energy to melt)/(mass of the unknown substance) = $\frac{1.20\times 10^{6}}{18.5}J/kg=6.49\times 10^{4}J/kg$

So, latent heat of fusion of the substance is $6.49\times 10^{4}J/kg$

7 0

3 years ago

The probability?????????????????

olga55 [171]

Answer: 4/20

Explanation:

7 0

2 years ago

What is the state of matter for 2NH3, 2NaCl and 2KNO3+PBI2.

Aloiza [94]

Answer:

2NH3 - Gas Phase

2 NaCl - Solid Phase

2KNO3+PBI2 - Aqueous Phase

Explanation:

2NH3 is ammonia gas which is colorless and has a bad pungent smell.

NaCl is salt. It has crystalline structure and can exhibit both aqueous or a liquid phase. Since there is no H2O molecule in the formula of NaCl, hence it is not aqueous. It is not liquid as well because liquid NaCl is represented as NaCl (l) while aqueous NaCl is represented as NaCl (aq).

The reaction 2KNO3+PBI2 will take place in aqueous phase and hence these two exists in aqueous phase

7 0

3 years ago