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3ca(s) + 2H3PO4(aq) -> Ca3(PO4)2(aq)+3H2(g) 1)a reaction between calcium and a solution of 1.2moldm-3 phosphoric acid produced 3 mol of H2 gas. a) Minimum volume of phosphoric acid would have been needed for reaction: I got 1.6cm3 b)Mass of calcium added...

8 years ago

The following questions are about the reaction of sodium oxide with nitric acid. 1)What mass of sodium oxide would be needed to react with acid to form 0.5 mol salt? I said 1.5 2) How much sodium oxide would be required to neutralise 230cm3 of 1.0moldm-3?...

8 years ago

How may particles are there in: in 1 mole of silicon? in 2 moles of fluorine? in 31g phosphorous? in 18g water? please help im confused especially with the last one and the second last one second

8 years ago

In 1346 the army of King Edward III of England defeated the forces of King Phillip VI of France at the battle of Crecy.The following passage gives some details: The main reason for Edward III's success was undoubtedly the longbow. The records say that ski...

8 years ago

One device used for throwing spears is an atlatl. This device was used by human hunters over 20000 years before the invention of the bow ad arrow. It effectively increases the length of the hunter's arm allowing a spear to be thrown further than it could...

8 years ago

A golf ball is stuck at point o on the ground and moves with an initial velocity of 20ms-1 at an angle of 53 degrees to the horizontal.The ball subsequently lands at a point x which is on the same horizontal levelas o. a) show that the time taken by the b...

8 years ago

1)A ball is thrown so that it initially travels at 10ms-1 at an angle of 70 above the horizontal a)a simple model assumes that the ball is thrown from ground level and lands at the samelevel.Find the time of flightand range of the ball. b)A refined model...

8 years ago

A ball is kicked from ground level so thta is intiial velocityis 10ms-1 AT AN angleof 60 degrees above the horizontal. It hits a wall which is at a distance of 8m from the initial position of the ball a)show that the ballhits the wall 1.6s after it was ki...

8 years ago

An arrow is fired horizontally with a speed of 30ms-1 from a height of 2m above the ground level. Model the arrow as a particle which does not experience air resistance. a)show that the time taken for the arrow to hit the ground is 0.639 seconds correct t...

8 years ago

DrBob222 I thought that 24,000 was for cm3 not dm3

8 years ago

Where did you get 22,400 from wouldnt you divide by 24000

8 years ago

I'm confused with the working out could you make it clearer please

8 years ago

When it says "HOW MUCH?" is it talking about the mass or the moles? If its talking about the moles is the answer 3 moles?

8 years ago

With that last line what is that equation and what is it used for?

8 years ago

Please help with this question I still need help specific to this question

8 years ago

Thanks for your help so far but I dont know what to write for these questions Drbob222 I only know how to answer clear questions saying "what is the configuration" so please help.

8 years ago

I dont get it the total is 160 and there are2 numbers so 2 fractions? and I dont get the x thing with 1-x AND 79(X)+81(1-X) iM VERY CONFUSED PLEASE HELP

8 years ago

DrBob222 please help with a i dont know what to do or what it is and for c that was what the question said and I'm still confused please tell me the steps specific to this.

8 years ago

IM VERY STUCK ON C

8 years ago

My teacher put in Ar=121.8 so we would know the ar to use if for the question if that helps yuo answer the question so you can hopefully help me

8 years ago

Forgot to post the other question for thisequation: 2) 2.00g of calcium was added to 500cm3 of 0.1moldm-3 and the solution was left until all the effervescence had stopped. a) What volume of 2 moldm-3 NaOH solution would be needed to neutralise th remaini...

8 years ago

is the last one 0.0416

8 years ago

I thought the last two were different I got for 31g phosphorous: 5.149501661 X 10-23 for 18g water: 2.990033223 X 10-23 Scott I dont get what you meant by your last two answers

8 years ago

Please help im sure i did it all wrong

8 years ago