If a student were to mix two solutions, one containing AgNO3, and another containing KBr, name one possible sign that a reaction has taken place

• The resulting solution is highly conductive

• The resulting solution has changed color

• The resulting solution's temperature does not change

• The resulting solution's mass is close to the sum of the two separate solutions

During a lab experiment, a student observed that the water in a beaker had all vaporized. The student has just witnessed a ______ change

Tags

NGSS.MS-PS1-4

By just looking at the following chemical reaction, with no prior knowlege of any of the compounds' properties, what is the most obvious sign a reaction has taken place?  $AgNO_{3\left(aq\right)}+KBr_{\left(aq\right)}\rightarrow AgBr_{\left(s\right)}+KNO_{3\left(aq\right)}$  

• Temperature change

• Gas formation

• Formation of a precipitate

• No reaction has occurred

Which of the following represents a correct net ionic equation?

•  $NaNO_{3\left(aq\right)}+NH_4Cl_{\left(aq\right)}\rightarrow NaCl_{\left(aq\right)}+NH_4NO_{3\left(aq\right)}$  

•  $6Fe^{2+}\rightarrow6Fe^{3+}+6e^-$  

•  $HCl_{\left(aq\right)}+NaOH_{\left(aq\right)}\rightarrow NaCl_{\left(aq\right)}+H_2O_{\left(l\right)}$  

•  $Ag_{\left(aq\right)}^++Cl_{\left(aq\right)}^-\rightarrow AgCl_{\left(s\right)}$  

Tags

NGSS.HS-PS1-7

Which of the following is the net ionic equation for a reaction between lead(II) nitrate and sodium iodide?

• $Pb\left(NO_3\right)_{2\left(aq\right)}+2NaI_{\left(aq\right)}\rightarrow PbI_{2\left(s\right)}+2NaNO_{3\left(aq\right)}$

• $Pb_{\left(aq\right)}^{2+}+I_{2\left(aq\right)}^-\rightarrow PbI_{2\left(s\right)}$

• $Pb_{\left(aq\right)}^{2+}+2I_{\left(aq\right)}^-\rightarrow PbI_{2\left(s\right)}$

• $2Na_{\left(aq\right)}^++2NO_{3\left(aq\right)}^-\rightarrow2NaNO_{3\left(aq\right)}$

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

 $2Ag_{\left(aq\right)}^++CrO_{4\left(aq\right)}^{2-}\rightarrow Ag_2CrO_{4\left(s\right)}$ 

is an example of a(n) __________ 

• Total Ionic Equation

• Net Ionic Equation

• Molecular Equation

• Acid-Base Equation

Which of the following represents a decomposition rection?

• 
• $O_2+2H_2\rightarrow2H_2O$

• 
• 
  $2H_2O\rightarrow2H_2+O_2$
  

If the red circles represent sodium, and the green represents chlorine, which of the two elements in the drawing is the limiting reactant for this reaction?
 $2Na^{ }+Cl_2^{ }\rightarrow2NaCl$  

• Sodium

• Chlorine

• Sulfur

• Hydrogen

A beaker was half filled with pure ethanol and placed over a burner. As the temperature of the ethanol reached 78°C, bubbling could be seen in the beaker. The gaseous contents of the bubbles were analyzed. The presence of which of the following substances would show that the bubbling was due to a physical change?

• Carbon dioxide

• Chlorine

• Water

• Ethanol

 If samples of $BaCl_2$ and  $Na_2SO_4$  are combined in solution and a precipitate forms, which of the following is evidence of ionic bonds having been formed in the precipitate?

• High melting point

• The solution does not conduct electicity

• Low melting point

• The solution is orange in color

Tags

NGSS.HS-PS1-3