Balance the equation
19 12 14
18 12 14
16 14 12
19 14 12
How to test oxygen gas?
use glowing splint
add ethane to burn
lime water turns milky
Which method can test chlorine
use damp red litmus paper
add lime water
use damp blue litmus paper
add NaOH solution
Which separation method uses boiling points?
Filtration
distillation
chromatography
decanting
In this reaction ,why aluminum is the reducing agent?
It gains oxygen
It's oxidation number decrease
It loses electrons
Fe formed
Phenolphthalein in KOH solution turns:
Pink
purple
yelow
orange
In experiment of measuring enthalpy.Why using polystyrene cup rather than using glass beaker.
plastic is lighter than glass
reduce heat loss
glass beaker may broke under high temperature
Which element is a liquid at room temperature?
Bromine
Chlorine
Diamond
Methane
What is the flame color for potassium ions?
Lilac
purple
red
blue
What is the flame color for calcium ions?
Lilac
brick red
yellow
blue
An element K in period 2 reacts with fluorine. What is the formula of the compound?
KF2
K2F
KF
no correct answers
Sodium chloride has a higher melting point than ethanol because
It has covalent bonds
It is polar compound
It forms an ionic lattice
It have higher Mr
which group does Z belong
Give the empirical formula of this organic compound
Sodium reacting with water produces?(formula of gas)