how can her observation be explained
before 2 beakers are in separate containers and during they bubble then after the water level goes down

• some atoms lost mass

• some atoms gained mass

• some atoms formed gases that escaped the container

• some atoms were destroyed

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

which of the following diagrams correctly represents the formation

• K^+[BR........]

• K--BR......

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

when an exothermic reaction occurs in water, the temperature____

• decreases because energy is absorbed by the reaction

• decreases because energy is released by the reaction

• increases because energy is absorbed by the reaction

• increases because energy is released by the reaction

Tags

NGSS.HS-PS3-4

the molecular model shown below is a trigonal planar
which formula will have this VSEPR molecular ge

• NH3

• PCI3

• BF3

• CH3

Ultraviolet rays can cause sunburn but visible light from a light buld

• Ultraviolet rays have longer wavelengths and more energy than visible light

• ultraviolet rays have shorter wavelengths and more energy than visible light

• ultraviolet rays have longer wavelengths and less energy than visible light

• ultraviolet rays have shorter wavelengths and less energy than visible light

Tags

NGSS.HS-PS4-3

NGSS.HS-PS4-5

Wave length C has many tall small waves what does that mean

• Wave C has the longest wavelength, highest frequency, and greatest energy

• wave C has the longest wavelength, lowest frequency, and lowest energy

• Wave C has the shortest wavelength, highest frequency, and greatest energy

• wave C has the shortest wavelength, lowest frequency and lowest energy

Tags

NGSS.HS-PS4-1

this graph starts out low and ends up higher
which statement correctly describes this reaction

• it is endothermic and energy is absorbed

• it is endothermic and energy is released

• it is exothermic and energy is absorbed

• it is exothermic and energy is released

Tags

NGSS.HS-PS1-4

which statement best describes the substance that results when electrons are transferred from

• it contains ionic bonds and has a very high melting point

• it contains ionic bonds and has a low melting point

• it contains covalent bonds and has a high melting point

• it contains covalent bonds and has a very low melting point

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

which statement correctly describes what occurs when a limiting reactant has been completely used

• when the limiting reactant has been used the excess reactant reacts with itself

• when the limiting reactant has been used, a different reaction occurs

• when the limiting reactant has been used the reaction stops

• more information is needed to predict what will occur

which of the following correctly pairs a chemical name with its chemical formula

• iron bromide, FeBr3

• Aluminum chloride Al3Cl

• Potassium nitrogen k3n

• sodium sulfide Na2S