Ask question

Ask question

All categories

1 year ago

5

Question 21 of 25 Which of the following requires a chemical change?

2 answers:

Vesna [10]1 year ago

3 0

Answer:

c . Letting the fizz escape from a soda

lilavasa [31]1 year ago

3 0

Answer: a

because there is a fire, it is a chemical change causing the marshmallow to melt.

You might be interested in

All synthetic elements...

ki77a [65]

In chemistry, a synthetic element is a chemical element that does not occur naturally on Earth, and can only be created artificially. So far, 24 synthetic elements have been created (those with atomic numbers 95–118). All are unstable, decaying with half-lives ranging from 15.6 million years to a few hundred microseconds.

Here is a picture am if It doesn't show up, I am sorry

4 0

3 years ago

What volume of a 6.67 M NaCl solution contains 3.12 mol NaCl? L

harkovskaia [24]

Answer:

0.47dm³

Explanation

Given parameters :

Molarity of NaCl = 6.67M

Number of moles = 3.12mol

Volume of NaCl =?

Volume of NaCl = number of moles/Molarity

Volume of NaCl = 3.12mol/6.67M

Volume of NaCl = 0.47dm³

4 0

3 years ago

Read 2 more answers

A human red blood cell is about 0.000008 meters in diameter which of the following represents this number in scientific notation

lukranit [14]

<u>Given:</u>

Diameter of a red blood cell = 0.000008

<u>To determine:</u>

The scientific notation corresponding to the given number

<u>Explanation:</u>

Scientific notation is a concise way of representing a very large or small number. It is written in two parts:

Given Number = Digits * Power of 10

In this case we have:

0.000008 = 8.0 * 10⁻⁶

3 0

3 years ago

What is the empirical formula of a substance that contains 5.28 g of c, 0.887 g of h, and 3.52 g of o?

kicyunya [14]

Not sure but I think it is C2H4O

8 0

2 years ago

Read 2 more answers

An important reaction that takes place in a blast furnace during the production of iron is the formation of iron metal and CO2 f

ladessa [460]

Answer: Mass of $Fe_2O_3$ required to form 930 kg of iron is 1328 kg

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For iron:

Given mass of iron = 930 kg = 930000 g (1kg=1000g)

Molar mass of iron = 56 g/mol

Putting values in equation 1, we get:

$\text{Moles of iron}=\frac{930000g}{56g/mol}=16607mol$

The chemical equation for the production of iron follows:

$Fe_2O_3+3CO\rightarrow 2Fe+3CO_2$

By Stoichiometry of the reaction:

2 moles of iron are produced by = 1 mole of $Fe_2O_3$

So, 16607 moles of iron will be produced by = $\frac{1}{2}\times 16607=8303moles$ of $Fe_2O_3$

Now, calculating the mass of $Fe_2O_3$ from equation 1, we get:

Mass of $Fe_2O_3$ = $moles\times {\text {molar mass}}=8303\times 160=1328480g=1328kg$

Thus mass of $Fe_2O_3$ required to form 930 kg of iron is 1328 kg

6 0

3 years ago