All categories

3 years ago

Am I correct?? Help please

Chemistry

2 answers:

anzhelika [568]3 years ago

8 0

Answer:

I would say you are correct.

Explanation:

Anuta_ua [19.1K]3 years ago

5 0

Answer:

I believe it'll be A (even though you chose it already).

Explanation:

You might be interested in

Can u please help me with these 2 answers!

Lelu [443]

5 is 2 I’m not sure about 4 though....

5 0

2 years ago

Compounds can be broken down by using what method?

Dima020 [189]

Answer:

chemical change

Explanation:

chemical change requires energy in the form of heat or electricity.

4 0

3 years ago

A scientist measures the standard enthalpy change for the following reaction to be 67.9 kJ:

bekas [8.4K]

Answer: The standard enthalpy of formation of $H_2O(g)$ is -252.1 kJ/mol.

Explanation:

The balanced chemical reaction is,

$Fe_2O_3(s)+3H_2(g)\rightarrow 2Fe(s)+3H_2O(g)$

The expression for enthalpy change is,

$\Delta H=[n\times H_f_{products}]-[n\times H_f_{reactantss}]$

Putting the values we get :

$\Delta H=[2\times H_f{Fe}+3\times H_f{H_2O}]-[1\times H_f{Fe_2O_3}+3\times H_f{H_2}]$

$67.9kJ=[(2\times 0)+(3\times H_f{H_2O})]-[(1\times -824.2kJ/mol)+3\times 0kJ/mol)]$

$H_f{H_2O}=-252.1kJ/mol$

Thus standard enthalpy of formation of $H_2O(g)$ is -252.1 kJ/mol.

3 0

2 years ago

The graph given below shows the motion of four runners P, Q, R, and S in a 5 km marathon.

wel

Answer:-

As we can see from the graphical data,

The distance covered by all the four runners is the same 5 km.

Among the four athletes, Athlete P covers the distance in under three hours.

It is the minimum time taken among the four athletes.

Thus Athlete P covers the 5 km distance in the minimum amount of time.

We know that speed = $\frac{Distance}{Time}$

Since time taken for P is minimum, his speed is the maximum. P ran the fastest.

Time taken by Q = 4.5 hours.

Speed of Q = $\frac{Distance}{Time taken by Q}$

= $\frac{5km}{4.5hour}$

= 1.1 km/ hr

Time taken by R = 6 hours.

Speed of R = $\frac{Distance}{Time taken by R}$

= $\frac{5km}{6hour}$

= 0.8 km/ hr

3 0

3 years ago

Describe two ways in which a cell grows.

adelina 88 [10]

Answer:

There are two types of cell division: mitosis and meiosis. Most of the time when people refer to “cell division,” they mean mitosis, the process of making new body cells.

3 0

2 years ago