Experience Chemistry

Which of the following steps are carried out after the data collection?

I Making observation

II Making conclusion

III Making hypothesis

IV Writing report

• I and III

• I and IV

• II and III

• II and IV

Tags

NGSS.HS-LS3-2

NGSS.HS-LS4-4

A student carries out an experiment to determine the rate of dissolving salt at different sizes.Which of the following apparatus is essential for the experiment?

• Conical flask

• Stopwatch

• Evaporating dish

• Bunsen burner

• Positively charged sphere
• Negatively charged electrons scattered in the sphere

Which of the following scientist proposed the model?

• John Dalton

• J.J. Thomson

• Ernest Rutherford

• Niels Bohr

Atom P
Proton No: 6
Nucleon No: 14

What is the number of neutrons in atom P?

• 6

• 7

• 8

• 12

Tags

NGSS.MS-PS1-1

How many atoms are there in 2 mol of chlorine gas?

[Avogardo constant: 6.02 x 10²³ mol^-1]

• 1.204 x 10²⁴

• 2.408 x 10²⁴

• 3.612 x 10²⁴

• 4.816 x 10²⁴

Calculate the relative formula mass of Zn(NO₃)₂.

[Relative atomic mass: Zn=65, N=14, O=16]

• 127

• 175

• 189

• 254

What is the emperical formula for this oxide?

• JO

• J₂O

• J₂O₃

• J₃O₂

Tags

NGSS.HS-PS1-7

Limewater turns milky and a black solid is formed. Which of the following equations correctly represent the reaction?

• Cu₂CO₃ ---> Cu₂O + CO₂

• CuCO₃ ---> CuO + CO₂

• CuCO₃ ---> CuO₂ + CO₂

• CuCO₂ ---> Cu + CO₂

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

What is the other name given to

Group 1?

• Halogen

• Noble gas

• Alkaline earth metal

• Alkali metal

Which of the following statements explain why the melting point and boiling point of Group 1 element decreases when going down the group in the periodic table?

• The number of proton increase.

• Size of atom increases.

• The relative mass of atom increases.

• The number of valence electron increases.