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shutvik [7]
3 years ago
9

What scientists do that is the basis for their investigations

Chemistry
1 answer:
galben [10]3 years ago
7 0
<span>The basis of any scientific investigation is a hypothesis and a research question. These guide your research and help you focus on an area that is narrow enough to study for meaningful results. The research question helps quantify how you are going to study the hypothesis.</span>
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What is the answer plzzzzzz help ASAP
zhuklara [117]

The answer is C) reactants because a chemical reaction is the process in which atoms present in the starting substance rearrange to give new chemical combinations present in the substance formed by the reaction
5 0
3 years ago
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Why does the sky change colors at sunrise and sunset
aniked [119]

Answer:

As the sun's angle changes, (because of the rotation of the earth) the sun slowly begins to shine more or less sunshine slowly. When sunsets and sunrises occur, the color of the sky changes because the sunshine is starting to fade out or in.

I put it in my own words so you don't have to worry about plagiarism :)

4 0
3 years ago
Calculate the amount of HCl in grams required to react with 3.75 g of CaCO3 according to the following reaction: CaCO3(s) + 2 HC
wolverine [178]

Answer:

The correct answer is 2.75 grams of HCl.

Explanation:

The given balanced equation is:  

CaCO₃ (s) + 2HCl (aq) ⇒ CaCl₂ (aq) + H₂O (l) + CO₂ (g)

Based on the given information, one mole of calcium carbonate is reacting with two moles of HCl. The molecular mass of HCl is 36.5 grams, thus, the mass of 2 moles of HCl will be, 36.5 × 2 = 73 grams

The molecular mass of CaCO₃ is 100 gram per mole, that is, the mass of 1 mole of CaCO₃ is 100 grams, therefore, the mass of HCl required for reacting with 3.75 grams of CaCO₃ will be,  

= 3.75 × 2 × 36.5 / 100 = 2.74 grams of HCl.  

8 0
3 years ago
Complete and balance the chemical equations for the precipitation reactions, if any, between the following pairs of reactants, a
Crank

Explanation:

a. Pb(NO_3)_2(aq) + Na_2SO_4(aq) → ?

Pb(NO_3)_2(aq) + Na_2SO_4(aq)\rightarrow PbSO_4(s)+2NaNO_3(aq)

Pb(NO_3)_2(aq)\rightarrow Pb^{2+}(aq)+2NO_3^{-}(aq)

Na_2SO_4(aq)\rightarrow 2Na^++SO_4^{2-}(aq)

Pb^{2+}(aq)+2NO_3^{-}(aq)+2Na^++SO_4^{2-}(aq)\rightarrow PbSO_4(s)+2Na^++2NO_3^{-}(aq)

Removing common ions from both sides, we get the net ionic equation:

Pb^{2+}(aq)+SO_4^{2-}(aq)\rightarrow PbSO_4(s)

b. NiCl_2(aq) + NH_4NO_3(aq) →

NiCl_2(aq) + NH4NO_3(aq) \rightarrow Ni(NO_3)_2+NH_4Cl(aq)

No precipitation is occuring.

c. Fe_Cl2(aq) + Na_2S(aq) →

FeCl_2(aq) + Na_2S(aq)\rightarrow FeS(s)+2NaCl(aq)

FeCl_2(aq)\rightarrow Fe^{2+}(aq)+2Cl^{-}(aq)

Na_2S(aq)\rightarrow 2Na^++S{2-}(aq)

Fe^{2+}(aq)+2Cl^{-}(aq)+2Na^++S^{2-}(aq)\rightarrow FeS(s)+2Na^++2Cl^{-}(aq)

Removing common ions from both sides, we get the net ionic equation:

Fe^{2+}(aq)+S^{2-}(aq)\rightarrow FeS(s)

d.MgSO_4(aq) + BaCl_2(aq) →

MgSO4(aq) + BaCl2(aq)\rightarrow BaSO_4(s)+MgCl_2

MgSO_4(aq)\rightarrow Mg^{2+}(aq)+SO_4^{2-}(aq)

BaCl_2(aq)\rightarrow Ba^{2+}+2Cl^{-}(aq)

Mg^{2+}(aq)+SO_4^{2-}(aq)+Ba^{2+}+2Cl^{-}(aq)(aq)\rightarrow BaSO_4(s)+Mg^{2+}(aq)+2Cl^{-}(aq)

Removing common ions from both sides, we get the net ionic equation:

Ba^{2+}(aq)+SO_4^{2-}(aq)\rightarrow BaSO_4(s)

5 0
3 years ago
When does the first step of digestion usually occur?
SVEN [57.7K]

Answer:

B.

when the food is chewed

Explanation:

first step is from your mouth when you chew the food

5 0
2 years ago
Read 2 more answers
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