Вопрос школьника по предмету Химия
Укажіть масову частку Нітрогену в калій нітраті KNO3:
А) 13,9% ;
Б) 14,3% ;
В) 20,3% ;
Г) 41,6 % .
Укажіть масову частку Нітрогену в калій нітраті KNO3:А) 13,9% ;Б) 14,3% ;В) 20,3% ;Г) 41,6 % .
Ответ учителя по предмету Химия
Ответ:
А) 13,9%
Объяснение:
М(KNO3)=39+14+16*3=101 г/моль
w(N)=14/101 * 100% = 13,86 % = 13,9 %
Похожие вопросы от пользователей
Answer the questions, Use the glossary on the right.
1 What computer system makes it possible to send letters very quickly?
2 What system allows computer users around the world to send and to obtain information?
3 What programs provide colourful pictures and sound?
4 What is the name of a computer-created «world», which seems almost completely real?
5 What is a special term, which means «to obtain stored information from a computer’s memory»?
6 What do we call a disk on which a large quantity of information can be stored?
7 What do you eall a sudden, unexpected computer failure?
8 What IS the term for the electrical or electronic components of a computer?
9 What do we call a large collection of data that is stored in a computer system?
10 What is the term for a set of instructions secretly put into a computer that destroys the information stored in it and stops it from working normally?
11 Where on the Internet can you look for information about products and services offered by a company or organisation?
12 What is WWW?
13 What store of informatIon can you easily put into your pocket?
14 What do we call a set of computer programs to control the operation of a computer?
15 What kind of computer can you use on the plane?
GLOSSARY
access — to find infonnation. especially on a computer
crash — a complete breakdown of a computer system or program
datahase — a large amount of infonnation stored in computer system
E-mail (electronic mail) — a system that allows messages to be sent from one computer to another
floppy disk (diskette) — a small removable magnetic disc which is used to store data
bard disk — magnetic disk inside a computer that stores data and programs
hardware — the electrical and mechanical pans of a computer system mcludmg the screen, the keyboard and lhe hard disk
laptop — a computer «mall enough to he held on one’s kneet for use
multimedia — the combination of sound. graphics and video to present information on a computer
software — programs that run a computer
the Internet — an mternatlonal network of computers
virtual reality (VR) — the effeset produced by using computer images to make places or situations look real when they are not
virus — program secretly introduced into a computer, which makes copies of itself and often damage other programt
web site (site) — a place on the Internet that gives you information about a particular subject or product
World Wide Web — the system lhat stores infonnation for computer users around the world
2)(5х+у)(у-5х)
помоите пожалуйста срочно
заранее спасибо