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3 years ago

How many grams of CaCl2 are need to prepare 250 mL of a 0.15M solution?

Chemistry

1 answer:

Tanzania [10]3 years ago

4 0

Answer:

Here is what I got from reading this question...

Explanation:

So if you dissolve 7.5625- g of CaCl2 in water, dissolve well and then add distilled in a 250- ml standard flask upto the mark and shake well for uniform Concentration, you will get 0.25- M CaCl2 solution.

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A plant living in the environment shown in the picture would have to be adapted not to loose to much water through its___

Ray Of Light [21]

Answer:

Many plants have thorns on their stems or leaves. What is the MOST likely explanation for the evolution of thorns?

A) Thorns help plants produce more food from photosynthesis.

B) Thorns are an example of a mutation that arises in the genetic code of plants.

C) Thorns help plants to conserve resources like water and soil nutrients that may be used by other organisms.

D) Thorns are an adaptation that some plants have evolved in order to discourage herbivores from eating the plant.

Explanation:

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3 years ago

Read 2 more answers

Anything in red is the question

laila [671]

Answer:

Question 19: the three are molecular compounds.

Question 20: CuSO₄.5H₂O

Explanation:

Question 19.

C₂H₄

H₂O₂

All of them are the combination of two kinds of different atoms in fixed proportions.

C₂H₄: two carbon atoms per four hydrogen atoms

HF: one hydrogen atom per one fluorine atom

H₂O₂: two hydrogen atoms per two oxygent atoms

Thus, they all meet the definition of compund: a pure substance formed by two or more different elements with a definite composition.

Molecular compounds are formed by covalent bonds and ionic compounds are formed by ionic bonds.

Two non-metal elements, like H-F, C - C, C - H, H-O, H - H, and O - O will share electrons forming covalent bonds to complete their valence shell. Thus, the three compounds are molecular and not ionic.

Question 20. Formula of copper(II) sulfate hydrate with 36.0% water.

Copper(II) sulfate is CuSO₄. Its molar mass is 159.609g/mol

Water is H₂O. Its molar mass is 18.015g/mol

Calling x the number of water molecules in the hydrate, the percentage of water is:

$\dfrac{18.015x}{18.015x+159.609}=36\%\\ \\ \\ \dfrac{18.015x}{18.015x+159.609}=0.36$

From which we can solve for x:

$18.015x=6.4854x+57.45924\\ \\ 11.5296x=57.45924\\ \\ x\approx4.98\approx5$

Thus, there are 5 molecules of water per each unit of CuSO₄, and the formula is:

CuSO₄.5H₂O

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3 years ago

As part of her nuclear stress test, Simone starts to walk on the treadmill. When she reaches the maximum level, Paul injects a r

Naya [18.7K]

Answer:

Part A: 36 MBq; Part B: 18 MBq

Explanation:

The half-life is the time it takes for half the substance to disappear.

The activity decreases by half every half-life

A =Ao(½)^n, where n is the number of half-lives.

Part A

3.0 da = 1 half-life

A = Ao(½) = ½ × 72 MBq = 36 MBq

Part B

6.0 da = 2 half-lives

A = Ao(½)^2 = ¼ × 72 MBq = 18 MBq

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3 years ago

Some of the most dangerous conditions occur when temperatures are hovering around _______ degrees fahrenheit, or freezing, when

Olin [163]

Answer:

32 ° F

Explanation:

Freezing temp for water is 32 degrees at 1 atm

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2 years ago

Name the stellar process in which the fusion of hydrogen produces other elements.

Vilka [71]

Hydrogen fusion generates the energy for proton - proton chains and the carbon nitrogen oxygen cycle. It is the nuclear fusion of 4 protons to form a helium 4 nucleus.

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3 years ago