1. underline the correct item.
i watched/ was watching a film when my cat jumped/ was jumping on me.
she was buying/ bought a new pair of shoes last sunday.
pete was sleeping/ slept while joe listened/ was listening to a new cd.
we were having/ had dinner when someone was knocking/ knocked on the door.
they were walking/ walked to school last monday because there was no bus.
mum was planting/ planted flowers when it started/ was starting to rain.
i ate/ was eating an apple while my sister drank/ was drinking some milk.
2. put when or while.
you can't imagine what happened yesterday while we were walking in the park.
we were walking there it started to rain.
it started to rain we went into the cafe.
we were sitting in the cafe a famous footballer came in.
we saw him everybody in the cafe jumped up and ran to him for the autographs.
i was running to him i stumbled my feet.
i was falling off i knocked the table and hit the footballer.
we saw that we were all together on the floor we started to laugh. at the end he presented me his t-shirt and an autograph. what a day!
3. put the verbs in brackets in the correct tense.
we went (go) shopping yesterday.
i (have) lunch while my mum -up).
jeff (watch) tv at 7 o'clock yesterday evening.
what / do) yesterday? - i (have) as very busy day. i (help) my granddad in the garden. we (dig) the garden all day long.
4. what did finn and sue did yesterday? use the cues and write a story. use the past simple or the past continuous.
be/ beautiful/ sunday morning - it was a beautiful sunday morning.
finn and sue/ decide/ to take/ their dog/ for a walk/ in the park
sue/ sit/ bench/ read/ magazine/ while/finn/ walk/ with the dog
in half an hour / finn/ come/ back/ alone
they/ look/ for dog/ everywhere/ but/ not find / him
when/ get dark/ they/ decide/ return home
when/ they/ arrive home/ dog/ lie in front of the door
Ca₃PO₄+6H₂O=3Ca(OH)₂+2PH₃
2PH₃+4O₂=P₂O₅+3H₂O
P₂O₅+H₂O=2HPO₃
HPO₃+H₂O=H₃PO₄
2)3NaOH+H₃PO₄=Na₃PO₄+3H₂O
3Na(+)+3OH(-)+3H(+)+PO₄(3-)=3Na(+)+PO₄(3-)+3H₂O
3OH(-)+3H(+)=3H₂O,сокращаем на 3,получается:
OH(-)+H(+)=H₂O
2FeCl₃+3Ca(OH)₂=2Fe(OH)₃+3CaCl₂
2Fe(3+)+6Cl(-)+3Ca(2+)+6OH(-)=2Fe(OH)₃+3Ca(2+)+6Cl(-)
2Fe(3+)+6OH(-)=2Fe(OH)3,сокращаем на 2,получается:
Fe(3+)+3OH(-)=Fe(OH)3
3)NaNO3(не подвергается гидролизу,потому что образована сильной кислотой и основанием)
FeCl₃-основана слабым основанием и сильной кислотой,гидролиз идет по катиону
1 ступень
FeCl3+HOH⇔FeOHCl2+HCl
Fe(3+)+3Cl(-)+H2O⇔FeOH(2+)+2Cl(-)+H(+)+Cl(-)
Fe(3+)+H2O⇔FeOH(2+)+H(+)
2 ступень
FeOHCl2+H2O⇔Fe(OH)2Cl+HCl
FeOH(2+)+2Cl(-)+H2O⇔Fe(OH)2(+)+Cl(-)+H(+)+Cl(-)
FeOH(2+)+H2O⇔Fe(OH)2(+)+H(+)
3 ступень
Fe(OH)2Cl+H2O⇔Fe(OH)3+HCl
Fe(OH)2(+)+Cl(-)+H2O⇔Fe(OH)3+H(+)+Cl(-)
Fe(OH)2(+)+H2O⇔Fe(OH)3+H(+)
KNO2-сильное основание,слабая кислота,гидролиз по аниону
KNO2+HOH⇔KOH+HNO2
K(+)+NO2(-)+HOH⇔K(+)+OH(-)+HNO2
NO2(-)+HOH⇔HNO2+OH(-)