What type of system is a home, school, or room?

an animal refuge park has 120 gazelles.If the population increases by 5% in one year, how manu gazells will the park have next y

Aneli [31]

120 x 1.05 = 126 gazelles next year.
If you times it by 105% then you get the answer of adding 5% on.

8 0

3 years ago

An aqueous KNO3 solution is made using 72.5 g of KNO3 diluted to a total solution volume of 2.00 L. Calculate the molarity, mola

Sonja [21]

Answer:

The molarity is 0.359 $\frac{moles}{L}$

The molality is 0.354 $\frac{moles}{kg}$

The mass percent of the solution es 3.45%

Explanation:

Molarity is a unit of concentration that indicates the amount of moles of solute that appear dissolved in each liter of the mixture. It is determined by:

$Molarity (M)=\frac{number of moles of solute}{volume}$

Being:

K: 39 g/mole
N: 14 g/mole
O: 16 g/mole

The molar mass of KNO₃ is:

KNO₃= 39 g/mole + 14 g/mole + 3*16 g/mole= 101 g/mole

You can apply the following rule of three: if 101 grams of KNO₃ are present in 1 mole, 72.5 grams in how many moles are present?

$moles of KNO_{3}=\frac{72.5 grams*1 mole}{101 grams}$

moles of KNO₃= 0.718

So you have:

moles of KNO₃= 0.718
volume= 2 L

Applying this quantity in the definition of molarity:

$molarity=\frac{0.718 moles}{2 L}$

Molarity= 0.359 $\frac{moles}{L}$

The molarity is 0.359 $\frac{moles}{L}$

Molality is a way of measuring the concentration of solute in solvent and indicates the amount of moles of solute in each kilogram of solvent.

Then the molality is calculated by:

$Molality=\frac{moles of solute}{mass of solvent in kilograms}$

Density is defined as the property that matter, whether solid, liquid or gas, has to compress in a given space. That is, it is the amount of mass per unit volume. So, if the density of 1.05 g / mL for the solution indicates that in 1 mL of solution there are 1.05 grams of solution, in 2000 mL (where 2L = 2000 mL, because 1 L = 1000mL) how much mass is there?

$mass=\frac{2000 mL*1.05 grams}{1 mL}$

mass= 2100 grams

Since mass solution = mass water + mass KNO₃

then mass water = mass solution - mass KNO₃

Being mass solution 2100 grams and mass KNO₃ 72.5 grams, and replacing you get: mass water= 2100 grams - 72.5 grams

mass water= 2,027.5 grams

Then, being:

moles of KNO₃= 0.718
mass of solvent in kilograms= 2.0275 kg (being 2,027.5 grams= 2.0275 kilograms because 1,000 grams= 1 kilogram)

Replacing in the definition of molality:

$molality=\frac{0.718 moles}{2.0275 kg}$

molality= 0.354 $\frac{moles}{kg}$

The molality is 0.354 $\frac{moles}{kg}$

The mass percent of a solution is the number of grams of solute per 100 grams of solution. Then the mass percent is the mass of the element or solute divided by the mass of the compound or solute and the result of which is multiplied by 100 to give a percentage.

$mass percent=\frac{mass of solute}{mass of solution} *100$

So, in this case:

$mass percent=\frac{72.5 grams}{2100 grams} *100$

mass percent= 3.45 % KNO₃ by mass

The mass percent of the solution es 3.45%

3 0

2 years ago

Tom lost money on his peach crops because they kept freezing in the winter. How could Tom most likely solve the problem of his p

vova2212 [387]

Answer:

B. He could breed his peach plants with peach plants that can survive the frost.

Explanation:

Tom can best solve his problem by breeding his peach plants with the ones that can survive the frost.

This is known cross breeding
The goal of cross breeding is to produce offspring that contains the traits of both of the parents or an improved hybrid.
If Tom can cross breed the failing peaches with the successful winter resistant ones, he can ensure better production.
The new hybrid will therefore will be genetically superior and adapted to the prevailing environmental changes.

5 0

3 years ago

What is the molar mas of zinc

Black_prince [1.1K]

The molar mass of Zinc is 65.38 u

Hope this helps :)

3 0

3 years ago

Read 2 more answers

How many moles of electrons are required to reduce one mole of bromine gas (Br2) to two moles of bromide ions (Br-)? 1 e- 2 e- 3

rosijanka [135]

The correct answer would be the second option. It would would need 2 moles of electrons to reduce one mole of bromine gas into two moles of the bromide ions. This is a reduction reaction. It would be written as:

Br2 = 2Br- + 2e-

8 0

3 years ago