Ask question

Ask question

All categories

2 years ago

8

Which represents the greatest time frame in which a short-term environmental change can occur? A)in days. B)in minutes. C)over h

undreds of years. D)over thousands of years.

1 answer:

dangina [55]2 years ago

5 0

Answer:

Over hundreds of years

Explanation:

Just did the test and got it right

You might be interested in

Explain why we would only ever see a full moon at night

Dafna11 [192]

Answer:

The moon is only visible during part of each month. ... When the moon is opposite the sun in the sky (which is when full moon happens), it will rise as the sun sets and set as the sun rises. Therefore, a full moon will be up all night long, but not during the day.

Explanation:

8 0

3 years ago

6. If 0.500 mol NaN3 react, what mass in grams of nitrogen will result?

lions [1.4K]

Answer:

21 g of N₂ are produced by the decomposition

Explanation:

The reaction is: 2 NaN3 → 2 Na + 3 N2

2 moles of sodium nitride decompose in order to produce 2 moles of Na and 3 moles of nitrogen gas.

According to stoichiometry, ratio is 2:3. Therefore we say,

2 moles of nitride can produce 3 moles of N₂

Then, 0.5 moles of NaN₃ will produce (0.5 . 3) / 2 = 0.75 moles of N₂

We convert the moles to mass, to find the answer

0.75 mol . 28 g / 1 mol = 21 g

7 0

2 years ago

Group viia elements are very active non metals give reason

Marianna [84]

Answer:

because they need only one electron

4 0

3 years ago

How are hypotheses different from theories?

juin [17]

Answer:

Explanation:

This is the Difference Between a Hypothesis and a Theory. In scientific reasoning, a hypothesis is an assumption made before any research has been completed for the sake of testing. A theory on the other hand is a principle set to explain phenomena already supported by data.

4 0

3 years ago

If you are given the molarity of a solution, what additional information would you need to find the weight/weight percent (w/w%)

Ludmilka [50]

Answer:

- The molar mass of the solute, in order to convert from moles of solute to grams of solute.

- The density of solution, to convert from volume of solution to mass of solution.

Explanation:

Hello,

In this case, since molarity is mathematically defined as the moles of solute divided by the volume of solution and the weight/weight percent as the mass of solute divided by the mass of solution, we need:

- The molar mass of the solute, in order to convert from moles of solute to grams of solute.

- The density of solution, to convert from volume of solution to mass of solution.

For instance, if a 1-M solution of HCl has a density of 1.125 g/mL, we can compute the w/w% as follows:

$w/w\%=1\frac{molHCl}{L\ sln}*\frac{36.45gHCl}{1molHCl}*\frac{1L\ sln}{1000mL\ sln}*\frac{1mL\ sln}{1.125g\ sln} *100\%\\\\w/w\%=3.15\%$

Whereas the first factor corresponds to the molar mass of HCl, the second one the conversion from L to mL of solution and the third one the density to express in terms of grams of solution.

Regards.

4 0

2 years ago