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3 years ago

How does building a model help scientist?

Chemistry

1 answer:

ahrayia [7]3 years ago

3 0

It gives the scientist a visual figure to look at and think about.

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The unit meter per second per second (m/s²) would be used to measure

Y_Kistochka [10]

Answer:

$\boxed{\text{A) Acceleration}}$

Explanation:

m/s is the unit for speed, so (m/s)/s is the rate of change of speed.

The rate of change of speed is acceleration.

B), C), and D) are wrong. They all have the units of m/s.

5 0

3 years ago

HELP PLSSSSSSSSSS

Nat2105 [25]

Answer:

ask your mom

Explanation:

copy this \pink{ \rule{999pt}{999999pt}}

and the result is here

btw if you want to change color change the \pink (if you want?)

$\red{ \rule{999pt}{999999pt}}$

8 0

3 years ago

A chemist has two solutions of H2SO4. One has a 40% concentration and the other has a 25% concentration.

vodomira [7]

Answer:

16 liters of the solution with 40% concentration must be mixed with 62 liters of the solution with 25% concentration in order to obtain 78 liters, 25% concentration solution.

Explanation:

Let the required volume of solution 1 be represented by x.

The required volume of solution 2 would then be 78-x.

The number of moles of solution 1 that would be required = 0.4x

The number of moles of solution 2 that would be required = 0.25(78-x)

The number of moles of the final mixture = 78 x 0.28 = 21.84

moles of solution 1 + moles of solution 2 = moles of final mixture

0.4x + 0.25(78 - x) = 21.84

0.4x + 19.5 - 0.25x = 21.84

0.4x - 0.25x = 21.84 - 19.5

0.15x = 2.34

x = 15.6 liters

To the nearest tenth = 16 liters

Liters of 40% solution needed = 16 liters

Liters of 25% solution needed = 78 - 16 = 62 liters.

Hence, 16 liters of the solution with 40% concentration must be mixed with 62 liters of the solution with 25% concentration in order to obtain 78 liters, 25% concentration solution.

7 0

3 years ago

Use the standard reaction enthalpies given below to determine ΔH°rxn for the following reaction: P4(g) + 10 Cl2(g) → 4PCl5(s) ΔH

Pie

Answer: -1835 kJ

Explanation:

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to Hess’s law, the chemical equation can be treated as algebraic expressions and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

$PCl_5(s)\rightarrow PCl_3(g)+Cl_2(g)$ $\Delta H_1=+157kJ$ (1)