17. True or False: Proximal means farther away from the point of attachment of the limb. *

According to the following position vs. Time graph the bicyclist was

julia-pushkina [17]

Answer:

According to the following position vs. Time graph the bicyclist was : D

D. Not moving for the first two seconds, then begin moving at the constant speed.

Explanation:

$Speed = \frac{Distance}{time}$

Along Y-axis = Distance in meters

Along X-axis = Time taken in second

For first 2 seconds the The object has not changed its position.There is Zero distance covered.So , Speed = 0
After 2 second,The Object changed the distance by equal amount in equal interval of time.(Uniform Speed).Hence at each point after 2 second, there is same value speed

3 0

4 years ago

A chemist needs to find the concentration of a solution of barium hydroxide.

Brums [2.3K]

Method 1: gravimetry

advantages: Impurities in the sample can be identified

disadvantages: The process is long, because it goes through several stages

Method 2: titration

advantages: the process is fast, because the titrate and titrant react immediately

disadvantages: Sometimes the determination of the end point of the titration is carried out too fast or too slowly so that the calculations carried out are inaccurate

3 0

2 years ago

From the amount of NaOH added at the 1st equivalence point, calculate the original molarity of the acid. Carry out the same calc

gizmo_the_mogwai [7]

Answer:

Molarity of acid, Ca = Cb*Vb*A/Va*B

Explanation:

Using H2SO4 as acid, the reaction is as follow:

2NaOH + H2SO4 ⇒ Na2SO4 + 2H2O

Volume of acid = Va; Volume of base = Vb, Molar concentration of acid = Ca; Molar concentration of base = Cb; Molarity of acid = A and Molarity of base = B

Ca*Va/Cb*Vb =A/B

∴ Ca = Cb*Vb*A/Va*B

4 0

3 years ago

How does a nuclear reactor produce electricity?

aleksley [76]

Answer:

Nuclear reactors are the heart of a nuclear power plant. They contain and control nuclear chain reactions that produce heat through a physical process called fission. That heat is used to make steam that spins a turbine to create electricity

6 0

3 years ago

A 3.24-gram sample of NaHCO3 was completely decomposed in an experiment. 2NaHCO3 → Na2CO3 + H2CO3 In this experiment, carbon dio

Stolb23 [73]

Answer:

a) mass of the H2CO3 produced:

given:

Mass of sample = 3.24 g

Mass of Na2CO3 obtained after decomposition = 2.19 g

Solution :

Molar mass of NaHCO3 = 84

reaction:

2NaHCO3 → Na2CO3 + H2CO3

so it is clear that 2 mole of NaHCO3 gives 1 mole of Na2CO3 and H2CO3

Now, ICE table for the reaction is :

NaHCO3 Na2CO3 H2CO3

I 3.24/84 0 0

C -2x +x +x

E 3.24/84 -2x x x

As NaHCO3 is completely decomposed so final Concentration of NaHCO3 is zero.

=> 3.24/84 -2x = 0

=> 2x = 3.24/84

=> x = 1.62/84

The new ICE table is :

NaHCO3 Na2CO3 H2CO3

I 3.24/84 0 0

C -2x = -2(1.62/84) +x = 1.62/84 +x = 1.62/84

E 0 1.62/84 1.62/84

From the above ICE table,

it is found that (1.62/84 ) moles of H2CO3 is obtained.

Since,

The molar mass of H2CO3 is 62

=> Mass of H2CO3 obtained = moles × molar mass

=> Mass of H2CO3 obtained = (1.62 /84 ) × 62

= 1.19 grams

Mass of H2CO3 experimentally :

Mass of reactants = mass of products

=> Mass of sample = mass of Na2CO3 + mass of H2CO3

=> Mass of H2CO3 = mass of sample - mass of Na2CO3

= 3.24 - 2.19 = 1.05 g

b) Experimental mass = 1.05 g

Theoretical mass = 1.19 g

Percentage yield of H2CO3 = Experimental mass × 100 / Theoretical mass

= 1.05 × 100 /1.19

= 88.23 %

6 0

3 years ago