Trộn 200ml đ có hòa tan MgSO4 1M với 300ml đ có hòa tan NaOH 2M lọc tách được kết tủa và đ sau khi lọc

a) viết pt

b) Tính khối lượng chất rắn thu được sau khi nung

c)tính nồng độ mol có trong đ sau khi lọc

I ............(have) a party until 11 pm last night

I..............(meet) tom again since we ..................(leave) school

He pays us a visit once or twice a month ,but he rarely (stay)........ longer than an hour

I didn't meet Steve because when I ........(arrive) ,he .......(go)to school

the house is dirty because it ...............(not,clean) for a week

last night,the fire .........(break) out when everybody...........(sleep)

he............(stand) under the tree when it .........(begin) to rain

I .........(not,send) the parcel until I......(hear) from you

Mr. Brown never ........(go) to bed before 10 o'clock every night

I........(speak) to Mr anh Mrs.Gibbons only last week just befofore they .......(die)in that terrible train accident

Michael..........(laugh) when I told him he joke

The last timeI .......(go) skiing was ten years ago

You .............(not,meet) the director yet?Now ,it's your chance to do so

Everyone...........(not,like) her because she is selfish

She ................(ask) me to speak to him several timesi

David was born after his father ..............(die)

Up to then I ...........(never,see) such a fat man

Last month I.............(be) in the hospital for ten days

Some animals .................(not,eat) during winter

There .............(be) no improvement since he.................(suggest) applying his new project last month

I..............(call) you as soon as I have finished my work

During the last two weeks,I..................(read) six chapters this book

He ......(offer) the job even though his qualifications were poor

Two hundred miles .......(be) a long distance

You..........(ever,see) a ghót in your life?

When we ..............(get) to the station , the train (already,leave)

Mary ...........(phone) you as soon as she ...........(come) the USA

Helen ...........(have) dinner when we ........(arrive) yesterday

It .............(probably .rain)tomorrow

He ..........(not,like)in his hometown for more than ten years

John .........(watch) TV at 8 last night

he ..............(often,say) OK when he ........(talk) with the guests

I (have)........ bread and milk for breakfast every day

they (start)...... learning english 7 years ago

it(sometimes,rain)........ in the summer

Bad workers never(work)........hảd

he (visit).......his friend yesterday and (find).....that he was our